INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Schedule of Components and Changes in Income Tax Expense (Benefit) and Respective Balance Sheet Items [Line Items]
Effective tax rate	12.00%		13.20%	(9.20%)	14.90%
Deferred income tax				$ (27,581)	$ (766)
Excess tax benefit	$ 5,440		$ 4,138	10,130	$ 5,832
Taxes payable, noncurrent	56,540			56,540		$ 59,874
Check the Box Election
Schedule of Components and Changes in Income Tax Expense (Benefit) and Respective Balance Sheet Items [Line Items]
Deferred income tax	706			25,340
Tax Cuts and Jobs Act
Schedule of Components and Changes in Income Tax Expense (Benefit) and Respective Balance Sheet Items [Line Items]
Provisional income tax expense	0	$ 2,157
Tax payable	66,478			66,478
Taxes payable, noncurrent	$ 55,841			$ 55,841