| 
           Business Segments and Customer Information (Details) (USD $) In Thousands, unless otherwise specified 
         | 
        12 Months Ended | 
      
      
        | 
           Dec. 31, 2012 
         | 
        
           Dec. 31, 2011 
         | 
        
           Dec. 31, 2010 
         | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Number of reportable operating segments | 
        4
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        $ 546,755
 | 
        $ 580,762
 | 
        $ 810,955
 | 
      
      
        | Income before income taxes | 
        43,852
 | 
        32,392
 | 
        37,741
 | 
      
      
        | Interest (income) expense, net | 
        7,224
 | 
        3,685
 | 
        199
 | 
      
      
        | Depreciation and amortization expense | 
        19,795
 | 
        13,467
 | 
        7,589
 | 
      
      
        | Capital expenditures | 
        20,863
 | 
        6,635
 | 
        4,805
 | 
      
      
        | Total assets | 
        410,211
 | 
        454,512
 | 
         
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        546,755
 | 
        580,762
 | 
        810,955
 | 
      
      
        | Percentage of revenue by customer (in dollars per share) | 
        10000.00%
 | 
        10000.00%
 | 
        10000.00%
 | 
      
      
        | 
           U.S. Army/Army Reserve [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        182,412
 | 
        231,615
 | 
        463,378
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        182,412
 | 
        231,615
 | 
        463,378
 | 
      
      
        | Percentage of revenue by customer (in dollars per share) | 
        3340.00%
 | 
        3990.00%
 | 
        5710.00%
 | 
      
      
        | 
           U.S. Navy [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        120,867
 | 
        140,551
 | 
        198,833
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        120,867
 | 
        140,551
 | 
        198,833
 | 
      
      
        | Percentage of revenue by customer (in dollars per share) | 
        2210.00%
 | 
        2420.00%
 | 
        2450.00%
 | 
      
      
        | 
           U.S. Air Force [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        6,963
 | 
        11,971
 | 
        13,304
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        6,963
 | 
        11,971
 | 
        13,304
 | 
      
      
        | Percentage of revenue by customer (in dollars per share) | 
        130.00%
 | 
        200.00%
 | 
        170.00%
 | 
      
      
        | 
           Total Department of Defense [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        310,242
 | 
        384,137
 | 
        675,515
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        310,242
 | 
        384,137
 | 
        675,515
 | 
      
      
        | Percentage of revenue by customer (in dollars per share) | 
        5680.00%
 | 
        6610.00%
 | 
        8330.00%
 | 
      
      
        | 
           U.S. Postal Service [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        130,866
 | 
        75,964
 | 
        0
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        130,866
 | 
        75,964
 | 
        0
 | 
      
      
        | Percentage of revenue by customer (in dollars per share) | 
        2390.00%
 | 
        1310.00%
 | 
        0.00%
 | 
      
      
        | 
           Department of U.S. Treasury [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        33,369
 | 
        41,434
 | 
        49,332
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        33,369
 | 
        41,434
 | 
        49,332
 | 
      
      
        | Percentage of revenue by customer (in dollars per share) | 
        610.00%
 | 
        710.00%
 | 
        610.00%
 | 
      
      
        | 
           Department of Interior [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        16,884
 | 
        24,254
 | 
        29,810
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        16,884
 | 
        24,254
 | 
        29,810
 | 
      
      
        | Percentage of revenue by customer (in dollars per share) | 
        310.00%
 | 
        420.00%
 | 
        370.00%
 | 
      
      
        | 
           Department of Energy [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        20,898
 | 
        23,010
 | 
        21,717
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        20,898
 | 
        23,010
 | 
        21,717
 | 
      
      
        | Percentage of revenue by customer (in dollars per share) | 
        380.00%
 | 
        400.00%
 | 
        270.00%
 | 
      
      
        | 
           Other government [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        32,231
 | 
        28,160
 | 
        29,598
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        32,231
 | 
        28,160
 | 
        29,598
 | 
      
      
        | Percentage of revenue by customer (in dollars per share) | 
        590.00%
 | 
        480.00%
 | 
        360.00%
 | 
      
      
        | 
           Total Federal civilian agencies [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        234,248
 | 
        192,822
 | 
        130,457
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        234,248
 | 
        192,822
 | 
        130,457
 | 
      
      
        | Percentage of revenue by customer (in dollars per share) | 
        4280.00%
 | 
        3320.00%
 | 
        1610.00%
 | 
      
      
        | 
           Commercial [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        2,265
 | 
        3,803
 | 
        4,983
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        2,265
 | 
        3,803
 | 
        4,983
 | 
      
      
        | Percentage of revenue by customer (in dollars per share) | 
        40.00%
 | 
        70.00%
 | 
        60.00%
 | 
      
      
        | 
           Federal Group [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        140,424
 | 
        184,147
 | 
        454,660
 | 
      
      
        | Income before income taxes | 
        10,130
 | 
        6,099
 | 
        20,574
 | 
      
      
        | Interest (income) expense, net | 
        291
 | 
        (75)
 | 
        (31)
 | 
      
      
        | Depreciation and amortization expense | 
        3,093
 | 
        2,906
 | 
        4,115
 | 
      
      
        | Capital expenditures | 
        763
 | 
        547
 | 
        496
 | 
      
      
        | Total assets | 
        30,130
 | 
        29,653
 | 
         
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        140,424
 | 
        184,147
 | 
        454,660
 | 
      
      
        | 
           International Group [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        167,193
 | 
        206,746
 | 
        261,499
 | 
      
      
        | Income before income taxes | 
        5,604
 | 
        5,342
 | 
        9,376
 | 
      
      
        | Interest (income) expense, net | 
        448
 | 
        (21)
 | 
        197
 | 
      
      
        | Depreciation and amortization expense | 
        3,035
 | 
        1,903
 | 
        1,521
 | 
      
      
        | Capital expenditures | 
        83
 | 
        573
 | 
        816
 | 
      
      
        | Total assets | 
        31,485
 | 
        49,734
 | 
         
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        167,193
 | 
        206,746
 | 
        261,499
 | 
      
      
        | 
           IT, Energy and Management Consulting Group [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        94,225
 | 
        106,817
 | 
        94,796
 | 
      
      
        | Income before income taxes | 
        11,802
 | 
        12,440
 | 
        10,275
 | 
      
      
        | Interest (income) expense, net | 
        14
 | 
        (73)
 | 
        (49)
 | 
      
      
        | Depreciation and amortization expense | 
        3,753
 | 
        3,256
 | 
        1,953
 | 
      
      
        | Capital expenditures | 
        53
 | 
        236
 | 
        305
 | 
      
      
        | Total assets | 
        64,502
 | 
        70,108
 | 
         
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        94,225
 | 
        106,817
 | 
        94,796
 | 
      
      
        | 
           Infrastructure Group [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Total assets | 
        0
 | 
        27,372
 | 
         
 | 
      
      
        | 
           Supply Chain Management Group [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenues | 
        144,913
 | 
        83,052
 | 
        0
 | 
      
      
        | Income before income taxes | 
        23,282
 | 
        15,965
 | 
        0
 | 
      
      
        | Interest (income) expense, net | 
        729
 | 
        350
 | 
        0
 | 
      
      
        | Depreciation and amortization expense | 
        9,914
 | 
        5,402
 | 
        0
 | 
      
      
        | Capital expenditures | 
        341
 | 
        113
 | 
        0
 | 
      
      
        | Total assets | 
        193,214
 | 
        203,241
 | 
         
 | 
      
      
        | Revenue, Major Customer [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Revenue, by customer | 
        144,913
 | 
        83,052
 | 
        0
 | 
      
      
        | 
           Corporate/unallocated [Member] 
         | 
         
 | 
         
 | 
         
 | 
      
      
        | Segment Reporting Information [Line Items] | 
         
 | 
         
 | 
         
 | 
      
      
        | Income before income taxes | 
        (6,966)
 | 
        (7,454)
 | 
        (2,484)
 | 
      
      
        | Interest (income) expense, net | 
        5,742
 | 
        3,504
 | 
        82
 | 
      
      
        | Capital expenditures | 
        19,623
 | 
        5,166
 | 
        3,188
 | 
      
      
        | Total assets | 
        $ 90,880
 | 
        $ 74,404
 | 
         
 |