Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Taxes [Line Items]
Provision for income taxes	$ 62,355	$ 62,344	$ 38,838	$ 21,445
Net discrete tax (expense) benefit	(800)	$ 15,100	2,800	$ 51,400
Capital loss carryforward	300,000		$ 300,000
Capital loss carryforward expiration period			5 years
Reasonably possible changes to unrecognized tax benefits related to settlement of tax audits and/or expiration of statutes of limitations within the next twelve months	$ 3,000		$ 3,000