Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Tax Examination [Line Items]
Valuation allowance	$ 4,200,000		$ 4,200,000
Effective tax rate			37.60%	1.50%
Income tax expense	5,387,000	4,000	21,934,000	298,000
Excess tax benefits from stock-based awards			$ 12,700,000
Earliest Tax Year [Member] | Federal Tax Jurisdiction [Member]
Income Tax Examination [Line Items]
Years subject to income tax examination			2011
Latest Tax Year [Member] | Federal Tax Jurisdiction [Member]
Income Tax Examination [Line Items]
Years subject to income tax examination			2013