Quarterly report pursuant to Section 13 or 15(d)

Business Segments and Customer Information, Major Customers (Details)

v3.8.0.1
Business Segments and Customer Information, Major Customers (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Revenue, Major Customer [Line Items]    
Revenues $ 176,897 $ 197,294
Percentage of revenue by customer 100.00% 100.00%
U.S. Postal Service    
Revenue, Major Customer [Line Items]    
Revenues $ 44,031 $ 46,469
Percentage of revenue by customer 24.90% 23.60%
U.S. Navy    
Revenue, Major Customer [Line Items]    
Revenues $ 42,585 $ 52,496
Percentage of revenue by customer 24.10% 26.60%
U.S. Army    
Revenue, Major Customer [Line Items]    
Revenues $ 42,787 $ 54,101
Percentage of revenue by customer 24.20% 27.40%
U.S. Air Force    
Revenue, Major Customer [Line Items]    
Revenues $ 2,281 $ 1,018
Percentage of revenue by customer 1.30% 0.50%
Total - DoD    
Revenue, Major Customer [Line Items]    
Revenues $ 87,653 $ 107,615
Percentage of revenue by customer 49.60% 54.50%
Commercial aviation    
Revenue, Major Customer [Line Items]    
Revenues $ 31,535 $ 31,804
Percentage of revenue by customer 17.80% 16.10%
Other commercial    
Revenue, Major Customer [Line Items]    
Revenues $ 3,588 $ 3,129
Percentage of revenue by customer 2.00% 1.60%
Total - Commercial    
Revenue, Major Customer [Line Items]    
Revenues $ 35,123 $ 34,933
Percentage of revenue by customer 19.80% 17.70%
Other government    
Revenue, Major Customer [Line Items]    
Revenues $ 10,090 $ 8,277
Percentage of revenue by customer 5.70% 4.20%