SHARE REPURCHASE - Narrative (Details) - USD ($)			12 Months Ended
	Jun. 04, 2018	Sep. 09, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Repurchase [Line Items]
Purchase of company stock			$ 181,402,000	$ 0	$ 12,315,000	$ 4,600,000
Stock repurchase program, authorized amount		$ 75,000,000
Stock repurchase program, expiration date		Sep. 06, 2016
Shares repurchased (shares)					324,141	116,859
Shares repurchased, weighted average price per share (usd per share)					$ 37.96	$ 39.20
KKR Share Repurchase [Member]
Share Repurchase [Line Items]
Percentage of Shares Outstanding	7.10%
Purchase of company stock	$ 181,400,000
Discounted Closing Stock Price	$ 73.96
Percentage of Closing Stock Price	96.00%
Shares repurchased (shares)	2,418,304