EARNINGS PER SHARE (Basic and Diluted) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Basic, numerator:
Net income	$ 1,584	$ 12,940	$ 10,231	$ (6,103)	$ 4,989	$ 19,154	$ 19,967	$ 745	$ 18,652	$ 44,854	$ 46,177
Effect of unvested restricted stock unit awards									(138)	(450)	(2,300)
Adjusted net income									$ 18,514	$ 44,404	$ 43,877
Basic, denominator:
Weighted-average shares	25,669,280	25,724,550	25,791,026	25,822,522	25,936,709	26,009,344	26,021,874	26,051,038	25,751,544	26,013,716	25,993,255
Earnings per common share (in dollars per share)	$ 0.06	$ 0.50	$ 0.39	$ (0.24)	$ 0.19	$ 0.73	$ 0.76	$ 0.03	$ 0.72	$ 1.71	$ 1.69
Diluted, numerator:
Net income	$ 1,584	$ 12,940	$ 10,231	$ (6,103)	$ 4,989	$ 19,154	$ 19,967	$ 745	$ 18,652	$ 44,854	$ 46,177
Effect of unvested restricted stock unit awards									(137)	(443)	(2,300)
Adjusted net income									$ 18,515	$ 44,411	$ 43,877
Diluted, denominator:
Weighted-average shares	25,669,280	25,724,550	25,791,026	25,822,522	25,936,709	26,009,344	26,021,874	26,051,038	25,751,544	26,013,716	25,993,255
Effect of dilutive securities									505,026	516,411	357
Adjusted weighted-average shares and assumed conversions	26,272,487	26,211,524	26,246,868	25,822,522	26,415,839	26,508,482	26,593,451	26,588,518	26,256,570	26,530,127	25,993,612
Earnings per common share (in dollars per share)	$ 0.06	$ 0.49	$ 0.39	$ (0.24)	$ 0.19	$ 0.72	$ 0.74	$ 0.03	$ 0.71	$ 1.67	$ 1.69