INCOME TAXES (Effective Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Provision for income taxes at federal statutory rate									$ 62,898	$ 52,452	$ 61,007
Increase/ (decrease) in taxes resulting from:
Impact from U.S. Tax Act									0	(4,009)	74,632
Entity classification election deferred tax asset impact									0	(25,962)	0
GILTI and BEAT U.S. taxes									(926)	1,526	0
Excess tax benefits relating to stock-based compensation									(28,385)	(17,370)	(9,307)
Subsidiary withholding tax liability and related foreign tax credit									0	(4,850)
Subsidiary withholding tax liability and related foreign tax credit											4,850
Foreign tax expense and tax rate differential									(1,402)	(88)	(39,997)
Effect of permanent differences									3,264	2,724	3,205
State taxes, net of federal benefit									2,971	3,452	(116)
Change in valuation allowance									218	151	783
Stock-based compensation expense									571	652	6,908
Other									(740)	839	(420)
Total	$ 10,273	$ 12,967	$ 11,733	$ 3,496	$ 18,803	$ 369	$ 6,864	$ (16,519)	$ 38,469	$ 9,517	$ 101,545
Effective tax rate									12.80%	3.80%	58.30%
Net deferred tax assets resulting from the change in tax status of foreign subsidiaries	$ 25,962								$ 25,962
ASU 2016-09
Increase/ (decrease) in taxes resulting from:
Excess tax benefit									$ 28,385	$ 17,370	$ 9,307