Investment Securities, Part II (Details) (USD $)	9 Months Ended		12 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Sep. 30, 2012 PreTSL I [Member]	Sep. 30, 2012 PreTSL II [Member]	Sep. 30, 2012 PreTSL VI [Member]	Sep. 30, 2012 PreTSL VI [Member]	Jul. 03, 2012 PreTSL VI [Member]	Sep. 30, 2012 PreTSL XXVIII [Member]	Sep. 30, 2012 U.S. Treasury Securities and Obligations of U.S. Government Corporations & Agencies [Member]	Dec. 31, 2011 U.S. Treasury Securities and Obligations of U.S. Government Corporations & Agencies [Member]	Sep. 30, 2012 Obligations of States and Political Subdivisions [Member]	Dec. 31, 2011 Obligations of States and Political Subdivisions [Member]	Sep. 30, 2012 Mortgage-backed Securities: GSE Residential [Member]	Dec. 31, 2011 Mortgage-backed Securities: GSE Residential [Member]	Sep. 30, 2012 Trust Preferred Securities [Member] securities	Dec. 31, 2011 Trust Preferred Securities [Member] securities	Sep. 30, 2012 Other Securities [Member] securities	Dec. 31, 2011 Other Securities [Member]
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale, one year or less	$ 101,913,000									$ 91,083,000		$ 826,000		$ 10,004,000		$ 0		$ 0
Available-for-sale, after 1 through 5 years	342,520,000									82,440,000		22,976,000		227,349,000		0		9,755,000
Available-for-sale, after 5 through 10 years	79,864,000									1,952,000		29,853,000		48,059,000		0		0
Available-for-sale, after ten years	1,455,000									0		956,000		0		450,000		49,000
Total available-for-sale securities	525,752,000		478,916,000							175,475,000	166,066,000	54,611,000	41,202,000	285,412,000	261,833,000	450,000	719,000	9,804,000	9,096,000
Available-for-sale, Weighted Average Yield, Maturities Year One (in hundredths)	2.07%
Available-for-sale , Weighted Average Yield, Maturities After 1 through 5 Years (in hundredths)	2.59%
Available-for-sale, Weighted Average Yield, Maturities After 5 through 10 Years (in hundredths)	2.77%
Available-for-sale , Weighted Average Yield, Maturities After 10 Years (in hundredths)	3.50%
Available-for-sale , Weighted Average Yield, Maturities (in hundredths)	2.53%
Available-for-sale, Full Tax-equivalent Yield, Maturities Year One (in hundredths)	2.09%
Available-for-sale, Full Tax-equivalent Yield, Maturities After 1 through 5 Years (in hundredths)	2.71%
Available-for-sale, Full Tax-equivalent Yield, Maturities After 5 through 10 years (in hundredths)	3.38%
Available-for-sale, Full Tax-equivalent Yield, Maturities After Ten Years (in hundredths)	3.76%
Available-for-sale, Full Tax-equivalent Yield, Maturities (in hundredths)	2.70%
Tax rate used to calculate tax-equivalent yields (in hundredths)	34.00%
Percentage investment book value exceeds total stockholders' equity (in hundredths)	10.00%
Investment Securities Pledged as Collateral	276,455,000		286,568,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value	28,645,000		43,071,000							10,971,000	19,960,000	2,113,000	690,000	15,561,000	15,231,000	0	0	0	7,190,000
Less than 12 months, Unrealized Losses	(78,000)		(449,000)							(28,000)	(40,000)	(21,000)	0	(29,000)	(37,000)	0	0	0	(372,000)
12 months or longer, Fair Value	2,293,000		2,626,000							0	0	0	0	0	0	450,000	719,000	1,843,000	1,907,000
12 months or longer, Unrealized losses	4,528,000		4,999,000							0	0	0	0	0	0	4,524,000	4,906,000	4,000	93,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	30,938,000		45,696,000							10,971,000	19,960,000	2,113,000	690,000	15,561,000	15,231,000	450,000	719,000	1,843,000	9,096,000
Total Unrealized Losses	(4,606,000)		(5,448,000)							(28,000)	(40,000)	(21,000)	0	(29,000)	(37,000)	(4,524,000)	(4,906,000)	(4,000)	(465,000)
Number of securities in Unrealized Loss Positions																3	4	1
Trust Preferred Securities [Abstract]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Total			584,000
Details of Trust Preferred Securities [Abstract]
Book Value	4,974,000			513,000	809,000			123,000	3,652,000
Market Value	450,000			209,000	213,000				28,000
Unrealized Loss	(4,524,000)			(304,000)	(596,000)				(3,624,000)
Other than Temporary Impairment Recorded to-date	3,989,000			691,000	2,187,000		127,000		1,111,000
Interest Paid						11,500
Credit losses on trust preferred securities held [Abstract]
Beginning of period	4,116,000	3,230,000	3,230,000
Additions related to OTTI losses not previously recognized	0	0
Reductions due to sales	(127,000)	0
Reductions due to change in intent or likelihood of sale	0	0
Additions related to increases in previously recognized OTTI losses	0	584,000
Reductions due to increases in expected cash flows	0	0
End of period	$ 3,989,000	$ 3,814,000	$ 4,116,000