Investment Securities, Part II (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2013 securities	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
One year or less	$ 158,308,000	$ 158,308,000
After 1 through 5 years	185,188,000	185,188,000
After 5 through 10 years	153,661,000	153,661,000
After ten years	3,147,000	3,147,000
Fair Value	500,304,000	500,304,000		508,309,000
Available-for-sale, Weighted Average Yield, Maturities Year One (in hundredths)		1.59%
Available-for-sale , Weighted Average Yield, Maturities After 1 through 5 Years (in hundredths)		2.81%
Available-for-sale, Weighted Average Yield, Maturities After 5 through 10 Years (in hundredths)		2.44%
Available-for-sale , Weighted Average Yield, Maturities After 10 Years (in hundredths)		1.98%
Available-for-sale , Weighted Average Yield, Maturities (in hundredths)		2.29%
Available-for-sale, Full Tax-equivalent Yield, Maturities Year One (in hundredths)		1.62%
Available-for-sale, Full Tax-equivalent Yield, Maturities After 1 through 5 Years (in hundredths)		3.27%
Available-for-sale, Full Tax-equivalent Yield, Maturities After 5 through 10 years (in hundredths)		2.91%
Available-for-sale, Full Tax-equivalent Yield, Maturities After Ten Years (in hundredths)		3.03%
Available-for-sale, Full Tax-equivalent Yield, Maturities (in hundredths)		2.63%
Tax rate used to calculate tax-equivalent yields (in hundredths)		35.00%
Percentage investment book value exceeds total stockholders' equity (in hundredths)		10.00%
Investment Securities Pledged as Collateral	263,000,000	263,000,000		267,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value	328,780,000	328,780,000		13,663,000
Less than 12 months, Unrealized Losses	(12,059,000)	(12,059,000)		(35,000)
12 months or longer, Fair Value	174,000	174,000		585,000
12 months or longer, Unrealized losses	3,478,000	3,478,000		4,389,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	328,954,000	328,954,000		14,248,000
Total Unrealized Losses	(15,537,000)	(15,537,000)		(4,424,000)
Credit losses on trust preferred securities held [Abstract]
Beginning of period		3,989,000	4,116,000
Additions related to OTTI losses not previously recognized		0	0
Reductions due to sales / (recoveries)		(2,878,000)	(127,000)
Reductions due to change in intent or likelihood of sale		0	0
Additions related to increases in previously recognized OTTI losses		0	0
Reductions due to increases in expected cash flows		0	0
End of period	1,111,000	1,111,000	3,989,000
Number Of Trust Preferred Securities Sold	2
PreTSL XXVIII [Member]
Details of Trust Preferred Securities [Abstract]
Book Value	3,652,000	3,652,000
Market Value	174,000	174,000
Unrealized Gains (Losses)	(3,478,000)	(3,478,000)
Other-than- temporary Impairment Recorded To-date		1,111,000
U.S. Treasury securities and obligations of U.S. government corporations & agencies
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
One year or less	153,175,000	153,175,000
After 1 through 5 years	38,317,000	38,317,000
After 5 through 10 years	0	0
After ten years	0	0
Fair Value	191,492,000	191,492,000		182,169,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value	176,440,000	176,440,000		10,997,000
Less than 12 months, Unrealized Losses	(6,708,000)	(6,708,000)		(3,000)
12 months or longer, Fair Value	0	0		0
12 months or longer, Unrealized losses	0	0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	176,440,000	176,440,000		10,997,000
Total Unrealized Losses	(6,708,000)	(6,708,000)		(3,000)
Obligations of states and political subdivisions
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
One year or less	1,467,000	1,467,000
After 1 through 5 years	31,028,000	31,028,000
After 5 through 10 years	29,279,000	29,279,000
After ten years	2,903,000	2,903,000
Fair Value	64,677,000	64,677,000		56,207,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value	28,440,000	28,440,000		1,969,000
Less than 12 months, Unrealized Losses	(1,652,000)	(1,652,000)		(20,000)
12 months or longer, Fair Value	0	0		0
12 months or longer, Unrealized losses	0	0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	28,440,000	28,440,000		1,969,000
Total Unrealized Losses	(1,652,000)	(1,652,000)		(20,000)
Mortgage-backed securities: GSE residential
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
One year or less	1,661,000	1,661,000
After 1 through 5 years	115,843,000	115,843,000
After 5 through 10 years	120,392,000	120,392,000
After ten years	0	0
Fair Value	237,896,000	237,896,000		259,460,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value	119,910,000	119,910,000		697,000
Less than 12 months, Unrealized Losses	(3,689,000)	(3,689,000)		(12,000)
12 months or longer, Fair Value	0	0		0
12 months or longer, Unrealized losses	0	0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	119,910,000	119,910,000		697,000
Total Unrealized Losses	(3,689,000)	(3,689,000)		(12,000)
Trust preferred securities
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
One year or less	0	0
After 1 through 5 years	0	0
After 5 through 10 years	0	0
After ten years	174,000	174,000
Fair Value	174,000	174,000		585,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value	0	0		0
Less than 12 months, Unrealized Losses	0	0		0
12 months or longer, Fair Value	174,000	174,000		585,000
12 months or longer, Unrealized losses	3,478,000	3,478,000		4,389,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	174,000	174,000		585,000
Total Unrealized Losses	(3,478,000)	(3,478,000)		(4,389,000)
Number of securities in Unrealized Loss Positions	1	1		3
Credit losses on trust preferred securities held [Abstract]
Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds	1,400,000
Other securities
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
One year or less	2,005,000	2,005,000
After 1 through 5 years	0	0
After 5 through 10 years	3,990,000	3,990,000
After ten years	70,000	70,000
Fair Value	6,065,000	6,065,000		9,888,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value	3,990,000	3,990,000		0
Less than 12 months, Unrealized Losses	(10,000)	(10,000)		0
12 months or longer, Fair Value	0	0		0
12 months or longer, Unrealized losses	0	0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	3,990,000	3,990,000		0
Total Unrealized Losses	$ (10,000)	$ (10,000)		$ 0