Investment Securities, Part II (Details) (USD $)	3 Months Ended	6 Months Ended
	Sep. 30, 2013 securities	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
One year or less		$ 158,675,000
After 1 through 5 years		252,442,000
After 5 through 10 years		118,898,000
After ten years		3,820,000
Fair Value		533,835,000		508,309,000
Available-for-sale, Weighted Average Yield, Maturities Year One (in hundredths)		1.68%
Available-for-sale , Weighted Average Yield, Maturities After 1 through 5 Years (in hundredths)		2.62%
Available-for-sale, Weighted Average Yield, Maturities After 5 through 10 Years (in hundredths)		2.40%
Available-for-sale , Weighted Average Yield, Maturities After 10 Years (in hundredths)		2.11%
Available-for-sale , Weighted Average Yield, Maturities (in hundredths)		2.28%
Available-for-sale, Full Tax-equivalent Yield, Maturities Year One (in hundredths)		1.71%
Available-for-sale, Full Tax-equivalent Yield, Maturities After 1 through 5 Years (in hundredths)		2.94%
Available-for-sale, Full Tax-equivalent Yield, Maturities After 5 through 10 years (in hundredths)		2.92%
Available-for-sale, Full Tax-equivalent Yield, Maturities After Ten Years (in hundredths)		3.11%
Available-for-sale, Full Tax-equivalent Yield, Maturities (in hundredths)		2.57%
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		250,000,000		267,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value		347,286,000		13,663,000
Less than 12 months, Unrealized Losses		(11,319,000)		(35,000)
12 months or longer, Fair Value		835,000		585,000
12 months or longer, Unrealized losses		3,955,000		4,389,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		348,121,000		14,248,000
Total Unrealized Losses		(15,274,000)		(4,424,000)
Details of Trust Preferred Securities [Abstract]
Book Value		4,790,000
Market Value		835,000
Unrealized Gains (Losses)		(3,955,000)
Other-than- temporary Impairment Recorded To-date		3,989,000
Credit losses on trust preferred securities held [Abstract]
Beginning of period	3,989,000	3,989,000	4,116,000
Additions related to OTTI losses not previously recognized		0	0
Reductions due to sales / (recoveries)		0	0
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		3,989,000	4,116,000
Number Of Trust Preferred Securities Sold	2
PreTSL I
Details of Trust Preferred Securities [Abstract]
Book Value		400,000
Market Value		428,000
Unrealized Gains (Losses)		28,000
Other-than- temporary Impairment Recorded To-date		691,000
PreTSL II
Details of Trust Preferred Securities [Abstract]
Book Value		738,000
Market Value		260,000
Unrealized Gains (Losses)		(478,000)
Other-than- temporary Impairment Recorded To-date		2,187,000
PreTSL XXVIII [Member]
Details of Trust Preferred Securities [Abstract]
Book Value		3,652,000
Market Value		147,000
Unrealized Gains (Losses)		(3,505,000)
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		151,994,000
After 1 through 5 years		55,523,000
After 5 through 10 years		0
After ten years		0
Fair Value		207,517,000		182,169,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value		184,589,000		10,997,000
Less than 12 months, Unrealized Losses		(6,059,000)		(3,000)
12 months or longer, Fair Value		0		0
12 months or longer, Unrealized losses		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		184,589,000		10,997,000
Total Unrealized Losses		(6,059,000)		(3,000)
Obligations of states and political subdivisions
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
One year or less		1,528,000
After 1 through 5 years		29,344,000
After 5 through 10 years		24,901,000
After ten years		3,620,000
Fair Value		59,393,000		56,207,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value		27,264,000		1,969,000
Less than 12 months, Unrealized Losses		(1,697,000)		(20,000)
12 months or longer, Fair Value		0		0
12 months or longer, Unrealized losses		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		27,264,000		1,969,000
Total Unrealized Losses		(1,697,000)		(20,000)
Mortgage-backed securities: GSE residential
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
One year or less		2,457,000
After 1 through 5 years		167,575,000
After 5 through 10 years		90,015,000
After ten years		0
Fair Value		260,047,000		259,460,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value		131,451,000		697,000
Less than 12 months, Unrealized Losses		(3,545,000)		(12,000)
12 months or longer, Fair Value		0		0
12 months or longer, Unrealized losses		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		131,451,000		697,000
Total Unrealized Losses		(3,545,000)		(12,000)
Trust preferred securities
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
One year or less		688,000
After 1 through 5 years		0
After 5 through 10 years		0
After ten years		147,000
Fair Value		835,000		585,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value		0		0
Less than 12 months, Unrealized Losses		0		0
12 months or longer, Fair Value		835,000		585,000
12 months or longer, Unrealized losses		3,955,000		4,389,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		835,000		585,000
Total Unrealized Losses		(3,955,000)		(4,389,000)
Number of securities in Unrealized Loss Positions		3		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		2,008,000
After 1 through 5 years		0
After 5 through 10 years		3,982,000
After ten years		53,000
Fair Value		6,043,000		9,888,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, Fair Value		3,982,000		0
Less than 12 months, Unrealized Losses		(18,000)		0
12 months or longer, Fair Value		0		0
12 months or longer, Unrealized losses		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		3,982,000		0
Total Unrealized Losses		$ (18,000)		$ 0