STOCK BASED COMPENSATION - ACTIVITY (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Shares
Granted (in shares)	0	0	0
Stock Option Plans
Shares
Outstanding, beginning of year (in shares)	1,200
Exercised (in shares)	(600)
Outstanding, end of year (in shares)	600	1,200
Vested and expected to vest (in shares)	600
Exercisable, end of period (in shares)	600
Weighted Average Exercise Price
Outstanding, beginning of year (in dollars per share)	$ 31.00
Exercised (in dollars per share)	31.00
Outstanding, end of year (in dollars per share)	31.00	$ 31.00
Vested and expected to vest (in dollars per share)	31.00
Exercisable, end of period (in dollars per share)	$ 31.00
Weighted Average Remaining Contractual Term
Outstanding, end of period	2 months
Vested and expected to vest	2 months
Exercisable, end of period	2 months
Additional disclosures
Total unrecognized compensation cost related to nonvested stock options granted	$ 0
Aggregate Intrinsic Value
Outstanding, end of period	9,000
Vested and expected to vest	9,000
Exercisable, end of period	$ 9,000