CALCULATION OF WEIGHTED AVERAGE SHARES OUTSTANDING FOR EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Earnings Per Share [Abstract]
Net income	$ 32,424	$ 25,454	$ 61,214	$ 49,247	$ 60,776
Basic weighted average shares outstanding	32,250,514	32,982,126	32,323,635	32,957,920
Plus unvested restricted stock	81,095	69,401	98,652	94,285
Diluted weighted shares outstanding	32,331,609	33,051,527	32,422,287	33,052,205
Earnings per common share
Basic	$ 1.01	$ 0.77	$ 1.89	$ 1.49
Diluted	$ 1.00	$ 0.77	$ 1.89	$ 1.49