Summary of Significant Accounting Policies - Additional Information (Detail)			3 Months Ended								12 Months Ended
	Mar. 25, 2016 USD ($)	Jan. 22, 2016 USD ($)	Dec. 31, 2016 USD ($)	Oct. 01, 2016 USD ($)	Jul. 02, 2016 USD ($)	Apr. 02, 2016 USD ($)	Dec. 31, 2015 USD ($) Segment	Oct. 03, 2015 USD ($)	Jul. 04, 2015 USD ($)	Apr. 04, 2015 USD ($)	Dec. 31, 2016 USD ($) Segment	Dec. 31, 2015 USD ($) Segment	Dec. 31, 2014 USD ($)
Significant Accounting Policies [Line Items]
Number of reportable segments | Segment											2
Non-Current Deferred Income Taxes			$ 31,417,000				$ 28,125,000				$ 31,417,000	$ 28,125,000
Net (loss) income			2,836,000	$ 5,014,000	$ 3,861,000	$ 13,550,000	(65,173,000)	$ (9,515,000)	$ 1,782,000	$ (1,973,000)	$ 25,261,000	(74,879,000)	$ 19,867,000
Cash equivalent maturity period											three months or less
Production cost of contracts			11,340,000				$ 10,290,000				$ 11,340,000	$ 10,290,000
Operations proposed for sale | Segment							2					2
Goodwill impairment							$ 57,200,000				0	$ 57,243,000	$ 0
Goodwill			82,554,000				82,554,000				82,554,000	82,554,000
Carrying value of trade names							0	32,900,000				0
Provision for forward loss reserves			4,780,000				11,925,000				$ 4,780,000	11,925,000
Minimum
Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets (in years)											14 years
Income tax benefit percentage											50.00%
Maximum
Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets (in years)											18 years
Accrued Liabilities
Significant Accounting Policies [Line Items]
Provision for forward loss reserves							7,600,000	7,600,000				7,600,000
Other Long-term Liabilities
Significant Accounting Policies [Line Items]
Provision for forward loss reserves							2,400,000	2,400,000				2,400,000
Electronic Systems
Significant Accounting Policies [Line Items]
Goodwill			82,554,000				82,554,000				$ 82,554,000	82,554,000
Structural Systems
Significant Accounting Policies [Line Items]
Goodwill impairment							57,200,000					57,200,000
Goodwill			0				0				0	0
Forward loss provision								$ 10,000,000				10,000,000
Disposal Group Sold | Pittsburgh, Pennsylvania Operations | Electronic Systems
Significant Accounting Policies [Line Items]
Final sales price		$ 38,600,000
Net assets sold in disposal		24,000,000
Net liabilities sold in disposal		4,000,000
Transaction costs, discontinued operations		300,000
Gain (loss) on disposition of assets		$ 18,300,000
Disposal Group Sold | Miltec Operations | Electronic Systems
Significant Accounting Policies [Line Items]
Final sales price	$ 13,300,000
Net assets sold in disposal	15,400,000
Net liabilities sold in disposal	2,700,000
Transaction costs, discontinued operations	1,300,000
Gain (loss) on disposition of assets	$ (700,000)
Trade names
Significant Accounting Policies [Line Items]
Impairment of trade names							32,900,000
Scenario, Previously Reported
Significant Accounting Policies [Line Items]
Deferred tax assets							1,600,000					1,600,000
Error Correction, Deferred Tax Asset to Deferred Tax Liability
Significant Accounting Policies [Line Items]
Non-Current Deferred Income Taxes							$ 1,600,000					1,600,000
Net (loss) income												$ (1,600,000)
Accounting Standards Update 2015-03 | Other Long-term Liabilities
Significant Accounting Policies [Line Items]
Unamortized debt issuance expense			3,100,000								3,100,000
Accounting Standards Update 2015-03 | Other Long Term Assets
Significant Accounting Policies [Line Items]
Unamortized debt issuance expense			$ (3,100,000)								$ (3,100,000)