Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Provisions for loss contracts	$ 66,500		$ 66,500		$ 94,000
Deferred pre-production costs	20,300		20,300		$ 20,200
Net income (loss) attributable to noncontrolling interest	(1,670)	$ 1,040	(3,724)	$ (710)
Selling, general and administrative expenses	146,839	118,183	465,197	368,788
Interest expense, net	23,713	20,038	75,917	57,460
Other income (expense), net	$ 1,201	(443)	$ 5,958	5,304
Restatement Adjustment | Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Selling, general and administrative expenses		300		1,000
Interest expense, net		2,200		6,500
Other income (expense), net		$ 2,500		$ 7,500
Transferred at Point in Time
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue derived from performance obligations satisfied when control passes to customer (as a percent)			75.00%