ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME - Summary (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Loss
Balance at beginning of period	$ 1,312,941
Other comprehensive (loss) income before reclassifications	482	$ (4,041)	$ 3,980
Amounts reclassified to earnings		(52)	(27)
Other comprehensive income (loss)	482	(4,093)	3,953
Balance at end of period	1,314,288	1,312,941
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Loss
Balance at beginning of period	(1,864)	2,232	(1,721)
Other comprehensive (loss) income before reclassifications	485	(4,044)	3,980
Amounts reclassified to earnings		(52)	(27)
Other comprehensive income (loss)	485	(4,096)	3,953
Balance at end of period	(1,379)	(1,864)	2,232
Unrealized Gains On Available-For-Sale Debt Securities
Accumulated Other Comprehensive Loss
Balance at beginning of period	3	0
Other comprehensive (loss) income before reclassifications	(3)	3
Amounts reclassified to earnings		0
Other comprehensive income (loss)	(3)	3
Balance at end of period	0	3	0
Accumulated Other Comprehensive (Loss) Income
Accumulated Other Comprehensive Loss
Balance at beginning of period	(1,861)	2,232	(1,721)
Balance at end of period	$ (1,379)	$ (1,861)	$ 2,232