ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - SCHEDULE OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Loss
Balance at January 1	$ 153,131
Other comprehensive income (loss) before reclassifications	3,980	$ (657)	$ (581)
Amounts reclassified to earnings	(27)	0	0
Net current period other comprehensive income (loss)	3,953	(657)	(581)
Balance at December 31	993,346	153,131
Accumulated Other Comprehensive (Loss) Income
Accumulated Other Comprehensive Loss
Balance at January 1	(1,721)	(1,064)	(483)
Balance at December 31	$ 2,232	$ (1,721)	$ (1,064)