QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) (USD $) In Thousands, except Per 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
QUARTERLY FINANCIAL DATA (UNAUDITED)
Interest Income	$ 26,349	$ 26,832	$ 27,678	$ 27,909	$ 28,967	$ 30,345	$ 31,122	$ 31,177	$ 108,768	$ 121,611	$ 134,571
Net Interest Income	23,223	23,331	23,750	23,778	24,438	25,070	25,390	24,950	94,082	99,848	101,252
Net income	$ 7,279	$ 6,986	$ 6,982	$ 6,011	$ 6,026	$ 5,615	$ 7,626	$ 4,546	$ 27,258	$ 23,813	$ 14,802
Earnings per Common Share
Basic (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
Fully Diluted (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
Change in amount of earnings per share reported in first quarter 10Q due to redemption of preferred stock in the first quarter									$ 0.06