Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Tax Disclosure [Abstract]
(Provision) for income taxes	$ 18,139,000	$ 10,650,000	$ 36,718,000	$ 25,210,000
Effective income tax rate	10.90%	0.58%	3.73%	1.10%
Unrecognized tax benefit			Within the next twelve months
Increase in deferred tax asset			92,080,000
Related TRA liability recorded	78,300,000		78,300,000
Increase of additional paid-in capital	$ 13,800,000		$ 13,800,000
Amortization period for tax basis intangibles			15 years