EARNINGS PER COMMON SHARE (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Income
Net income attributable to common shareholders										$ 35,542,000
Redemption of preferred shares									$ 0
Net income attributable to common shareholders and assumed conversions									$ 38,323,000	$ 35,542,000	$ 28,996,000
Weighted Average Shares
Net income attributable to common shareholders (in shares)									23,105,317	21,637,775	20,706,688
Effect of dilutive warrants (in shares)									210,638	163,011	76,828
Effect of dilutive stock options (in shares)										108,584	70,552
Net income attributable to common shareholders and assumed conversions (in shares)									23,431,355	21,909,370	20,854,068
Earnings per Common Share
Net income attributable to common shareholders (in dollars per share)	$ 0.49	$ 0.49	$ 0.27	$ 0.41	$ 0.42	$ 0.42	$ 0.35	$ 0.45	$ 1.66	$ 1.64	$ 1.40
Net income attributable to common shareholders and assumed conversions (in dollars per share)	$ 0.48	$ 0.48	$ 0.27	$ 0.40	$ 0.42	$ 0.42	$ 0.35	$ 0.44	$ 1.64	$ 1.62	$ 1.39
Stock warrants
Weighted Average Shares
Effect of dilutive warrants (in shares)									210,638
Stock options
Weighted Average Shares
Effect of dilutive stock options (in shares)									115,400
Earnings per Common Share
Common shares not considered in computing diluted earnings per share										452	125,530