STOCKHOLDERS' EQUITY - Stock Repurchases (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 21, 2018
Equity [Abstract]
Repurchases paid (in shares)	980,000	96,000	1,078,000
Repurchases unsettled (in shares)	21,000	3,000	0
Stock Repurchase Program, Remaining Authorized Repurchase Amount [Roll Forward]
Authorization remaining, beginning of period	$ 34,892,000	$ 39,385,000	$ 40,534,000
Authorizations	27,003,000	0	25,879,000
Repurchases paid	(54,276,000)	(4,335,000)	(27,028,000)
Repurchases unsettled	(999,000)	(158,000)	0
Authorization remaining, end of period	$ 6,620,000	$ 34,892,000	$ 39,385,000
Amount authorized under share repurchase program				$ 50,000,000