STOCK-BASED COMPENSATION - Common Stock Repurchases (Details) - USD ($) shares in Millions	3 Months Ended				6 Months Ended		64 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019
Share-based Payment Arrangement [Abstract]
Authorized repurchase amount	$ 600,000,000.0				$ 600,000,000.0		$ 600,000,000.0
Repurchases of common stock (in shares)	(0.1)		(0.2)		(0.2)	(0.5)	(5.7)
Repurchases of common stock	$ (4,948,000)	$ (6,324,000)	$ (12,218,000)	$ (14,264,000)	$ (11,300,000)	$ (26,500,000)	$ (305,200,000)
Remaining available repurchase amount	$ 294,800,000				$ 294,800,000		$ 294,800,000