EARNINGS PER SHARE (Basic and Diluted) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Basic, numerator:
Net income	$ 16,270	$ 24,376	$ 4,888	$ 40,776	$ 1,233	$ 9,954	$ 45,534	$ 51,963
Effect of unvested restricted stock unit awards	(2)			(98)			(28)	(128)
Adjusted net income	$ 16,268			$ 40,678			$ 45,506	$ 51,835
Basic, denominator:
Weighted-average shares	25,527,982			25,697,509			25,550,365	25,670,435
Earnings per common share (in dollars per share)	$ 0.64			$ 1.58			$ 1.78	$ 2.02
Diluted, numerator:
Net income	$ 16,270	$ 24,376	$ 4,888	$ 40,776	$ 1,233	$ 9,954	$ 45,534	$ 51,963
Effect of unvested restricted stock unit awards	(2)			(94)			(28)	(124)
Adjusted net income	$ 16,268			$ 40,682			$ 45,506	$ 51,839
Diluted, denominator:
Weighted-average shares	25,527,982			25,697,509			25,550,365	25,670,435
Effect of dilutive securities	888,613			1,098,150			911,303	1,037,824
Adjusted weighted-average shares and assumed conversions	26,416,595			26,795,659			26,461,668	26,708,259
Earnings per common share (in dollars per share)	$ 0.62			$ 1.52			$ 1.72	$ 1.94