STOCK OPTIONS - Stock Option Activity (Details) - Stock option - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Shares
Outstanding at beginning of year (in shares)	1,499,795	1,190,295
Granted (in shares)	321,750	432,000
Exercised (in shares)	(49,400)	(55,000)
Forfeited/expired (in shares)	(94,500)	(67,500)
Outstanding at end of year (in shares)	1,677,645	1,499,795	1,190,295
Exercisable at end of year (in shares)	910,647	768,598
Weighted-Average Exercise Price
Outstanding at beginning of year (in dollars per share)	$ 13.11	$ 13.15
Granted (in dollars per share)	15.12	12.72
Exercised (in dollars per share)	12.24	9.02
Forfeited/expired (in dollars per share)	8.41	14.59
Outstanding at end of year (in dollars per share)	13.46	13.11	$ 13.15
Exercisable at end of year (in dollars per share)	13.00	12.75
Additional disclosure
Weighted-average fair value of options granted during the year (in dollars per share)	$ 4.05	$ 2.98	$ 2.72