ACCUMULATED OTHER COMPREHENSIVE LOSS - Summary (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Loss
Balance at beginning of period			$ 1,314,288
Other comprehensive income (loss)	$ 4,486	$ (1,674)	(2,082)	$ 188
Balance at end of period	1,292,322		1,292,322
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Loss
Balance at beginning of period	(7,993)	(191)	(1,379)	(1,861)
Other comprehensive income (loss)	5,253	(1,291)	(1,361)	379
Balance at end of period	(2,740)	(1,482)	(2,740)	(1,482)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Loss
Balance at beginning of period	(7,993)	(191)	(1,379)	(1,864)
Other comprehensive income (loss)	5,253	(1,291)	(1,361)	382
Balance at end of period	$ (2,740)	(1,482)	$ (2,740)	(1,482)
Unrealized Gains (Losses) On Available-For-Sale Debt Securities
Accumulated Other Comprehensive Loss
Balance at beginning of period				3
Other comprehensive income (loss)				(3)
Balance at end of period		$ 0		$ 0