Quarterly report pursuant to Section 13 or 15(d)

Business Segments and Customer Information - Major Customers (Details)

v3.19.2
Business Segments and Customer Information - Major Customers (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Revenue, Major Customer [Line Items]        
Revenues $ 189,111 $ 170,394 $ 359,030 $ 347,291
USPS        
Revenue, Major Customer [Line Items]        
Revenues 42,112 43,089 84,795 87,120
U.S. Navy        
Revenue, Major Customer [Line Items]        
Revenues 22,202 35,696 42,807 78,281
U.S. Army        
Revenue, Major Customer [Line Items]        
Revenues 47,333 41,548 84,052 84,335
U.S. Air Force        
Revenue, Major Customer [Line Items]        
Revenues 5,545 4,943 10,922 7,224
Total - DoD        
Revenue, Major Customer [Line Items]        
Revenues 75,080 82,187 137,781 169,840
Commercial aviation        
Revenue, Major Customer [Line Items]        
Revenues 54,086 34,037 102,561 65,572
Other commercial        
Revenue, Major Customer [Line Items]        
Revenues 5,090 3,444 10,174 7,032
Total - Commercial        
Revenue, Major Customer [Line Items]        
Revenues 59,176 37,481 112,735 72,604
Other government        
Revenue, Major Customer [Line Items]        
Revenues $ 12,743 $ 7,637 $ 23,719 $ 17,727
Customer Concentration Risk | Sales Revenue, Net        
Revenue, Major Customer [Line Items]        
Percentage of revenue by customer 100.00% 100.00% 100.00% 100.00%
Customer Concentration Risk | Sales Revenue, Net | USPS        
Revenue, Major Customer [Line Items]        
Percentage of revenue by customer 22.30% 25.30% 23.60% 25.10%
Customer Concentration Risk | Sales Revenue, Net | U.S. Navy        
Revenue, Major Customer [Line Items]        
Percentage of revenue by customer 11.80% 20.90% 11.90% 22.50%
Customer Concentration Risk | Sales Revenue, Net | U.S. Army        
Revenue, Major Customer [Line Items]        
Percentage of revenue by customer 25.00% 24.40% 23.40% 24.30%
Customer Concentration Risk | Sales Revenue, Net | U.S. Air Force        
Revenue, Major Customer [Line Items]        
Percentage of revenue by customer 2.90% 2.90% 3.10% 2.10%
Customer Concentration Risk | Sales Revenue, Net | Total - DoD        
Revenue, Major Customer [Line Items]        
Percentage of revenue by customer 39.70% 48.20% 38.40% 48.90%
Customer Concentration Risk | Sales Revenue, Net | Commercial aviation        
Revenue, Major Customer [Line Items]        
Percentage of revenue by customer 28.60% 20.00% 28.60% 18.90%
Customer Concentration Risk | Sales Revenue, Net | Other commercial        
Revenue, Major Customer [Line Items]        
Percentage of revenue by customer 2.70% 2.00% 2.80% 2.00%
Customer Concentration Risk | Sales Revenue, Net | Total - Commercial        
Revenue, Major Customer [Line Items]        
Percentage of revenue by customer 31.30% 22.00% 31.40% 20.90%
Customer Concentration Risk | Sales Revenue, Net | Other government        
Revenue, Major Customer [Line Items]        
Percentage of revenue by customer 6.70% 4.50% 6.60% 5.10%