EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net income	$ 29,934	$ 33,015	$ 31,118	$ 27,555	$ 22,064	$ 23,852	$ 20,563	$ 20,725	$ 121,622	$ 87,204	$ 76,648
Weighted Average Shares (in shares)
Basic Shares (in shares)	27,815,437	27,537,841	27,526,653	27,486,573	27,445,739	27,436,792	27,257,799	27,029,640	27,592,380	27,294,028	26,404,071
Effect of dilutive securities (in shares)	58,576	63,499	54,525	67,381	77,615	76,307	74,497	81,283	61,428	78,076	51,847
Weighted average common shares (diluted) (in shares)	27,874,013	27,601,340	27,581,178	27,553,954	27,523,354	27,513,099	27,332,296	27,110,923	27,653,808	27,372,104	26,455,918
Net Income Available to Common Shareholders per Share (in dollars per share)
Basic EPS (in dollars per share)	$ 1.08	$ 1.20	$ 1.13	$ 1.00	$ 0.80	$ 0.87	$ 0.75	$ 0.77	$ 4.41	$ 3.19	$ 2.90
Effect of Dilutive Securities (in dollars per share)									(0.01)	0
Diluted EPS (in dollars per share)	$ 1.07	$ 1.20	$ 1.13	$ 1.00	$ 0.80	$ 0.87	$ 0.75	$ 0.76	$ 4.40	$ 3.19	$ 2.90