Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Benefit from (provision for) income taxes	$ 791	$ (11,847)	$ 795	$ (9,041)
Pretax net income on tax provisions	4,245	5,815	11,795	15,959
Provisions for income taxes before discrete items	1,900	$ 3,300	$ 4,500	$ 6,100
U.S. statutory income tax rate			35.00%
Unrecognized tax benefits that would affect the effective tax rate if recognized	32,300		$ 32,300		$ 32,000
Gross unrecognized tax benefits decrease in next 12 months	5,000		5,000
Offset to deferred tax assets for unrecognized tax benefits			19,900
Estimated unrecognized tax benefits	12,439		12,439		12,030
Accrued interest and penalties related to unrecognized tax benefits	$ 600		$ 600		$ 500