Summary of Significant Accounting Policies - Revision of Previously Issued Financial Statements (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								6 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income before income taxes			$ 162,348	$ 156,912					$ 319,260	$ 642,919	$ 536,004	$ 512,943
Provision for income taxes			46,095	45,822					91,917	190,534	173,573	144,236
Net income	$ 95,424	$ 129,618	$ 116,253	$ 111,090	$ 52,830	$ 116,770	$ 98,678	$ 94,153	$ 227,343	$ 452,385	$ 362,431	$ 368,707
Basic earnings per share (in usd per share)	$ 1.03	$ 1.40	$ 1.25	$ 1.20	$ 0.57	$ 1.27	$ 1.07	$ 1.03	$ 2.46	$ 4.89	$ 3.94	$ 4.37
Diluted earnings per share (in usd per share)	$ 1.00	$ 1.36	$ 1.22	$ 1.17	$ 0.56	$ 1.24	$ 1.05	$ 1.00	$ 2.39	$ 4.75	$ 3.85	$ 4.24
Basic weighted average shares outstanding (in shares)	92,574	92,631	92,665	92,516	92,321	92,110	91,904	91,750	92,591	92,597	92,023	84,317
Diluted weighted average shares outstanding (in shares)	95,235	95,307	95,279	95,030	94,350	94,157	94,050	93,934	95,137	95,213	94,139	86,982
Adjustments to reconcile net income to net cash provided by operating activities:
Net cash provided by operating activities				$ 122,623					$ 212,042
Net cash used in investing activities				(20,745)					(37,924)
Net cash used in financing activities				(158,507)					(121,489)
Effect of foreign currency exchange rates on cash				8,795					(6,696)	$ (42,430)	$ (37,022)	$ (37,548)
Net (decrease) increase in cash				(47,834)					45,933	$ 27,866	$ (29,917)	$ 138,964
Scenario, Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income before income taxes			$ 162,348	156,912					319,260
Provision for income taxes			48,163	46,940					95,103
Net income			$ 114,185	$ 109,972					$ 224,157
Basic earnings per share (in usd per share)			$ 1.23	$ 1.19					$ 2.42
Diluted earnings per share (in usd per share)			$ 1.21	$ 1.17					$ 2.37
Basic weighted average shares outstanding (in shares)			92,665	92,516					92,591
Diluted weighted average shares outstanding (in shares)			94,549	94,329					94,437
Adjustments to reconcile net income to net cash provided by operating activities:
Net cash provided by operating activities				$ 121,505					$ 208,856
Net cash used in investing activities				(20,745)					(37,924)
Net cash used in financing activities				(157,389)					(118,303)
Effect of foreign currency exchange rates on cash				8,795					(6,696)
Net (decrease) increase in cash				(47,834)					45,933
Accounting Standards Update 2016-09 | Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income before income taxes			$ 0	0					0
Provision for income taxes			(2,068)	(1,118)					(3,186)
Net income			$ 2,068	$ 1,118					$ 3,186
Basic earnings per share (in usd per share)			$ 0.02	$ 0.01					$ 0.04
Diluted earnings per share (in usd per share)			$ 0.01	$ 0.00					$ 0.02
Basic weighted average shares outstanding (in shares)			0	0					0
Diluted weighted average shares outstanding (in shares)			729	701					700
Adjustments to reconcile net income to net cash provided by operating activities:
Net cash provided by operating activities				$ 1,118					$ 3,186
Net cash used in investing activities				0					0
Net cash used in financing activities				(1,118)					(3,186)
Effect of foreign currency exchange rates on cash				0					0
Net (decrease) increase in cash				$ 0					$ 0