STOCK-BASED COMPENSATION PLANS - Stock Options (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
Number of Shares
Outstanding at the beginning of the period (in shares) | shares	297,124
Granted (in shares) | shares	0
Exercised (in shares) | shares	(3,014)
Forfeited (in shares) | shares	(1,470)
Expired (in shares) | shares	(4,920)
Outstanding at the end of the period (in shares) | shares	287,720
Vested or expected to vest (in shares) | shares	285,559
Exercisable (in shares) | shares	260,307
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 11.55
Granted (in dollars per share) | $ / shares	0.00
Exercised (in dollars per share) | $ / shares	1.74
Forfeited (in dollars per share) | $ / shares	1.80
Expired (in dollars per share) | $ / shares	18.10
Outstanding at the end of the period (in dollars per share) | $ / shares	11.59
Vested or expected to vest (in dollars per share) | $ / shares	11.66
Exercisable (in dollars per share) | $ / shares	$ 12.58
Weighted Average Remaining Contractual Term (years)
Outstanding	4 years 4 months
Vested or expected to vest	4 years 3 months 22 days
Exercisable	4 years 12 days
Aggregate Intrinsic Value (in thousands)
Outstanding (in dollars) | $	$ 109
Vested or expected to vest (in dollars) | $	108
Exercisable (in dollars) | $	85
Total intrinsic values of stock options exercised (in dollars) | $	5
Cash received from the exercise of stock options (in dollars) | $	$ 5