SHARE-BASED COMPENSATION PLANS - Non-vested stock options (Details) - Non Vested Stock Options [Member] - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Outstanding at beginning of year	481,613	625,362
Number of Options, Granted	192,650	129,200
Number of Options, Vested	(193,838)	(243,798)
Number of Options, Forfeited	(6,685)	(29,151)
Number of Options, Outstanding at end of year	473,740	481,613
Weighted Average Exercise Price, Outstanding at beginning of year (in dollars per share)	$ 29.46	$ 26.55
Weighted Average Exercise Price, Granted (in dollars per share)	23.45	37.22
Weighted Average Exercise Price, Vested (in dollars per share)	27.59	26.42
Weighted Average Exercise Price, Forfeited (in dollars per share)	29.94	26.67
Weighted Average Exercise Price, Outstanding at end of year (in dollars per share)	27.77	29.46
Weighted Average Fair Value, Outstanding at beginning of year (in dollars per share)	4.49	3.43
Weighted Average Fair Value, Granted (in dollars per share)	3.32	7.07
Weighted Average Fair Value, Vested (in dollars per share)	3.87	3.25
Weighted Average Fair Value, Forfeited (in dollars per share)	4.87	3.46
Weighted Average Fair Value, Outstanding at end of the year (in dollars per share)	$ 4.26	$ 4.49