TREASURY STOCK - Narrative (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 11, 2018	Dec. 10, 2018
Treasury Stock Transactions, Excluding Value of Shares Reissued [Abstract]
Treasury stock (in shares)	2,900,000		2,900,000
Treasury stock	$ 120,100,000		$ 120,600,000
Treasury stock, average cost per share (in dollars per share)	$ 41.87		$ 41.87
Stock repurchase program, authorized amount (up to)				$ 225,000,000	$ 150,000,000
Amount available for share repurchase under this latest authorization	$ 225,000,000
Stock repurchased during period (in shares)	0	0