Accounting Pronouncements - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Income tax expense	$ (5,501)	$ 6,888	$ 386	$ 15,724
Decrease in operating of cash flow			19,281	57,088
Increase in financing of cash flow			(392,448)	(133,790)
ASU 2016-09
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Income tax expense	$ 200		$ 300
Decrease in operating of cash flow				(1,600)
Increase in financing of cash flow				$ 1,600