Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Provisions for loss contracts	$ 81,200		$ 81,200		$ 94,000
Deferred pre-production costs	18,700		18,700		$ 20,200
Net income (loss) attributable to noncontrolling interest	(1,145)	$ 135	(2,054)	$ (1,750)
Selling, general and administrative expenses	171,157	127,918	318,358	250,605
Interest expense, net	31,920	17,564	52,204	37,422
Other income (expense), net	$ 2,171	936	$ 4,757	5,747
Restatement Adjustment | Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Selling, general and administrative expenses		300		700
Interest expense, net		2,200		4,300
Other income (expense), net		$ 2,500		$ 5,000
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%