STOCK-BASED COMPENSATION (Fair Value of Restricted Stock and Restricted Stock Units Vested) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Service Period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested	$ 35,478	$ 27,038	$ 14,363
Performance Targets
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested	1,046	9,085	8,993
Equity Classified Award | Service Period | Equity-Settled Award | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested	142	12,607	11,431
Equity Classified Award | Service Period | Equity-Settled Award | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested	24,987	10,620	2,932
Equity Classified Award | Performance Targets | Equity-Settled Award | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested	0	452	690
Equity Classified Award | Performance Targets | Equity-Settled Award | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested	1,046	0	348
Liability Classified Award | Service Period | Cash-Settled Award | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested	10,349	3,811	0
Liability Classified Award | Performance Targets | Equity-Settled Award | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested	$ 0	$ 8,633	$ 7,955