BENEFIT PLANS, Deferred Compensation Plans for Directors (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Liability accrued for compensation plan	$ 13,328	$ 0
Deferred Compensation Plans for Directors [Member] | Directors [Member]
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Deferred compensation arrangement with individual, shares credited (in shares)	150,110	154,013
Liability accrued for compensation plan	$ 4,200	$ 4,000
Expense recognized under plan	$ 200	$ 200	$ 200