Effective Tax Rates (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Tax Disclosure [Abstract]
(Loss) income before income taxes	$ (144,018)	$ (2,639)	$ (152,411)	$ 51
Income tax benefit (provision)	$ 1,007	$ 503	$ 835	$ (60)
Effective tax rate	0.70%	19.10%	0.50%	117.60%