Income Taxes - Schedule of Deferred Income Taxes (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Accrued expenses	$ 1,363	$ 1,669
Allowance for doubtful accounts	134	94
Contract overrun reserves	4,412	1,766
Deferred compensation	491	464
Employment-related accruals	2,463	5,375
Environmental reserves	772	778
Federal tax credit carryforwards	7,031	2,696
Inventory reserves	2,703	3,873
Investment in common stock	297	300
Pension obligation	3,299	3,959
State net operating loss carryforwards	1,402	1,065
State net operating loss carryforwards	5,937	5,382
Stock-based compensation	2,165	2,082
Workers’ compensation	133	121
Other	1,595	1,072
Total gross deferred tax assets	34,197	30,696
Valuation allowance	(7,477)	(6,882)
Total gross deferred tax assets, net of valuation allowance	26,720	23,814
Deferred tax liabilities:
Depreciation	(11,802)	(12,485)
Goodwill	(2,035)	(12,105)
Intangibles	(37,891)	(51,755)
Prepaid insurance	(514)	(685)
Section 48(a) adjustment	(682)	(1,334)
Unbilled receivables	0	(1,115)
Total gross deferred tax liabilities	(52,924)	(79,479)
Net deferred tax liabilities	$ (26,204)	$ (55,665)