Income Taxes - Effective Income Tax Reconciliation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, Deduction, Amount [Abstract]
U.S. federal income tax expense at statutory rate	$ 138,750	$ 132,987	$ 29,815
U.S. state and local income tax expense (benefit), net of U.S. federal income tax effect	7,428	18,101	(4,495)
Recognition of state deferred tax assets and net operating losses, net of U.S. federal income tax effect	0	(16,242)	0
Nondeductible expenses	2,980	3,223	230
Federal research & development tax credits	(2,153)	(3,753)	(1,241)
Deduction for domestic production activities	(5,525)	0	0
Foreign taxes	471	(3,927)	(1,371)
Other, net	(1,220)	469	(185)
Provision for income taxes	$ 140,731	$ 130,858	$ 22,753