EARNINGS PER COMMON SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net Income/(Loss)
Net income	$ 7,279	$ 6,986	$ 6,982	$ 6,011	$ 6,026	$ 5,615	$ 7,626	$ 4,546	$ 27,258	$ 23,813	$ 14,802
Preferred dividends and discount accretion									(2,110)	(3,054)	(3,054)
Redemption of preferred shares									1,357
Net income attributable to common shareholders									26,505	20,759	11,748
Net income (loss) available to common shareholders and assumed conversions									$ 26,505	$ 20,759	$ 11,748
Weighted Average Shares
Net income (loss) available to common shareholders (in shares)									20,265,761	20,179,512	20,136,362
Effect of dilutive shares/warrants (in shares)									58,896	41,615	18,022
Net income available to common shareholders and assumed conversions (in shares)									20,324,657	20,221,127	20,154,384
Per Share Amount
Net income available to common shareholders (in dollars per share)	$ 0.34	$ 0.32	$ 0.32	$ 0.32	$ 0.26	$ 0.24	$ 0.34	$ 0.19	$ 1.31	$ 1.03	$ 0.58
Net income available to common shareholders and assumed conversions (in dollars per share)	$ 0.34	$ 0.32	$ 0.32	$ 0.32	$ 0.26	$ 0.24	$ 0.34	$ 0.19	$ 1.30	$ 1.03	$ 0.58
Stock options
Anti-dilutive securities
Common shares not considered in computing diluted earnings per share									289,544	254,850	262,441
Stock warrants
Anti-dilutive securities
Common shares not considered in computing diluted earnings per share									571,906	571,906	571,906