Segments - Schedule of Company's Segment Results (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Revenues, net	$ 225,150	$ 186,932	$ 639,670	$ 504,917
Operating income	111,255	85,834	314,582	231,757
Depreciation and amortization	18,060	13,591	48,579	36,920
Capital expenditures	5,240	5,203	15,348	13,634
North America [Member]
Segment Reporting Information [Line Items]
Revenues, net	115,266	101,495	335,346	291,593
Operating income	59,093	49,273	168,622	140,984
Depreciation and amortization	5,159	5,046	15,598	15,064
Capital expenditures	1,942	1,153	4,298	5,749
International [Member]
Segment Reporting Information [Line Items]
Revenues, net	109,884	85,437	304,324	213,324
Operating income	52,162	36,561	145,960	90,773
Depreciation and amortization	12,901	8,545	32,981	21,856
Capital expenditures	$ 3,298	$ 4,050	$ 11,050	$ 7,885