EARNINGS PER SHARE - (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
EARNINGS PER SHARE
Net income (loss) available for stockholders:	$ 5,266	$ (726)	$ (9,662)	$ (16,437)	$ (25,093)	$ (160,423)	$ (5,122)	$ (201,953)
Less: Adjustments for earnings attributable to participating securities	(41)			0				0
Net income (loss) used in calculating earnings per share	$ 5,225			$ (16,437)			$ (5,122)	$ (201,953)
Weighted average shares outstanding (including participating securities)	215,677			215,083			215,648	215,088
Adjustment for participating securities	(2,649)			(2,539)			(2,665)	(2,697)
Shares used in calculating basic earnings per share	213,028			212,544			212,983	212,391