EARNINGS PER SHARE (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
Earnings Per Share [Abstract]
Net income	$ 17,179	$ 20,484	$ 20,374	$ 18,611	$ 19,455	$ 18,594	$ 17,451	$ 9,460	$ 76,648	$ 64,960	$ 59,845
Weighted Average Shares (in shares)
Basic Shares (in shares)	26,710,029	26,324,316.000	26,304,129.000	26,275,323	26,238,004.000	26,200,621.000	26,149,593.000	24,959,865	26,404,071	25,891,382	23,899,562
Effect of dilutive securities (in shares)	60,022	53,072.000	47,885.000	43,409	52,772.000	63,493.000	71,819.000	80,215	51,847	68,566	93,815
Weighted average common shares (diluted) (in shares)	26,770,051	26,377,388	26,352,014	26,318,732	26,290,776.000	26,264,114.000	26,221,412.000	25,040,080	26,455,918	25,959,948	23,993,377.000
Net Income Available to Common Shareholders per Share (in dollars per share)
Basic EPS (in dollars per share)	$ 0.64	$ 0.78	$ 0.77	$ 0.71	$ 0.74	$ 0.71	$ 0.67	$ 0.38	$ 2.90	$ 2.51	$ 2.50
Effect of Dilutive Securities (in dollars per share)									0.00	(0.01)	(0.01)
Diluted EPS (in dollars per share)	$ 0.64	$ 0.78	$ 0.77	$ 0.71	$ 0.74	$ 0.71	$ 0.67	$ 0.38	$ 2.90	$ 2.50	$ 2.49