ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - NARRATIVE (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax expense (benefit)	$ (49,106,000)	$ 11,834,000	$ 1,758,000
Accumulated Other Comprehensive (Loss) Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax expense (benefit)	$ 0	$ 0	$ 0