Income Taxes - Summary of Provision for Income Taxes and U.S. Federal Tax Rate (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018		Jun. 30, 2019	Jun. 30, 2018	[1]
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount [Abstract]
Computed “expected” tax expense	$ 54,025	$ 48,547
Foreign income tax differential	(3,185)	1,907
Excess tax benefit related to stock-based compensation	(8,097)	(5,946)
State taxes net of federal benefits	2,982	3,396
Foreign-sourced nontaxable income	145	(6,291)
Foreign tax credit/transition tax - federal only	5,098	5,426
GILTI, net of foreign tax credits	3,284	4,921
Change in valuation allowance and remeasurement of related deferred tax asset	(64,880)	0
Other	6,237	2,363
Provision for income taxes	$ (4,391)	$ 54,323	[1]	$ 52,743	$ 108,705
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Computed “expected” tax expense	21.00%	21.00%
Foreign income tax differential	(1.20%)	0.80%
Excess tax benefit related to stock-based compensation	(3.20%)	(2.60%)
State taxes net of federal benefits	1.20%	1.50%
Foreign-sourced nontaxable income	0.10%	(2.70%)
Foreign tax credit/transition tax - federal only	1.90%	2.40%
GILTI, net of foreign tax credits	1.30%	2.10%
Change in valuation allowance and remeasurement of related deferred tax asset	(25.20%)	0.00%
Other	2.40%	1.00%
Provision for income taxes	(1.70%)	23.50%

[1] Reflects reclassifications from previously disclosed amounts to conform to current presentation.