Income Taxes - Summary of Provision for Income Taxes and U.S. Federal Tax Rate (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018		Mar. 31, 2017
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount [Abstract]
Computed tax expense at the U.S. federal tax rate	$ 48,157		$ 58,579
Foreign income tax differential	2,016		(5,843)
Excess tax benefits related to stock-based compensation	(4,624)		(8,721)
State taxes net of federal benefits	3,373		1,607
Foreign-sourced nontaxable income	(6,588)		(3,372)
Foreign withholding taxes	5,471		2,045
GILTI Tax, net of foreign tax credits	4,921		0
Other	1,656		(620)
Provision for income taxes	$ 54,382	[1]	$ 43,675
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Computed tax expense at the U.S. federal tax rate	21.00%		35.00%
Foreign income tax differential	0.90%		(3.50%)
Excess tax benefits related to stock-based compensation	(2.00%)		(5.20%)
State taxes net of federal benefits	1.50%		1.00%
Foreign-sourced nontaxable income	(2.90%)		(2.00%)
Foreign withholding taxes	2.40%		1.20%
GILTI Tax, net of foreign tax credits	2.10%		0.00%
Other	0.70%		(0.40%)
Provision for income taxes	23.70%		26.10%

[1] Reflects the January 1, 2018 adoption of Accounting Standards Update 2014-09, "Revenue from Contracts with Customers (Topic 606)" using the modified retrospective transition method. As a result of the application of the modified retrospective transition method, the Company's prior period results within its annual report on Form 10-K and quarterly reports on Form 10-Q will not be restated to reflect the impact of Topic 606. See footnote 1.