STOCK OPTIONS - Stock Options Granted (Details) - $ / shares			12 Months Ended
	Mar. 24, 2017	Aug. 27, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	70,000	38,750	70,000	0	38,750
Forfeited (in shares)		(12,250)	(3,000)	(8,250)	(4,000)
Outstanding (in shares)		26,500	93,500	26,500	34,750	0
Granted (in dollars per share)	$ 44.21	$ 42.03	$ 44.21	$ 0.00	$ 42.03
Vesting period (in years)		5 years
Expiration period (in years)		10 years
Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	46,250		46,250
Forfeited (in shares)	(3,000)
Outstanding (in shares)	43,250
Granted (in dollars per share)	$ 44.21
Vesting period (in years)	3 years
Expiration period (in years)	10 years
Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	23,750		23,750
Forfeited (in shares)	0
Outstanding (in shares)	23,750
Granted (in dollars per share)	$ 44.21
Vesting period (in years)	5 years
Expiration period (in years)	10 years