Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Tax Disclosure [Abstract]
Income tax expense	$ 14,600		$ 1,611	$ 12,820	$ 1,552
Loss on extinguishment of Convertible Notes, tax benefit				$ 2,800
Effective tax rate	36.10%		3.30%	36.10%	4.30%
Tax impacts of extinguishment of Convertible Notes to additional paid in capital				$ 4,400
Excess tax benefits from stock-based compensation				$ 13,572
Release of valuation allowance for deferred income taxes		$ 33,400