Significant Accounting Policies - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Segment Facility	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Significant Accounting Policies [Line Items]
Number of reportable segments | Segment	3
Number of manufacturing facilities | Facility	44
Income tax expense	$ 6,800
Net profit change on contracts	163,052	$ 6,663	$ (6,486)
Cash paid for debt prepayment	$ 31,600
Maturity period of highly liquid investments	Three months or less
Land and Buildings [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives	15 years
Land and Buildings [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives	40 years
Machinery and Equipment [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Machinery and Equipment [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives	12 years
Joint Venture [Member]
Significant Accounting Policies [Line Items]
Investment in joint venture	49.00%
ASU 2016-09 [Member]
Significant Accounting Policies [Line Items]
Reclassification of tax benefits from deferred taxes to retained earnings	$ 700
Accounting Standards Update 2014-09 [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Net profit change on contracts	$ 100