Securities (Details) (USD $)	3 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012 item	Sep. 30, 2013
Securities available for sale
Securities available for sale, amortized cost		$ 377,383,000	$ 400,498,000
Unrealized gains		9,245,000	5,655,000
Unrealized losses		188,000	5,090,000
Total securities available for sale, fair value		386,440,000	401,063,000
Securities available for sale sold	385,000
Loss on available for sale securities sold	5,000
Number of securities sold		0
Held to maturity securities		0	0
U.S. Treasury and other U.S. government obligations
Securities available for sale
Securities available for sale, amortized cost		98,000,000	40,000,000
Total securities available for sale, fair value		98,000,000	40,000,000
Government sponsored enterprise obligations
Securities available for sale
Securities available for sale, amortized cost		83,015,000	124,621,000
Unrealized gains		2,789,000	1,937,000
Unrealized losses		56,000	1,484,000
Total securities available for sale, fair value		85,748,000	125,074,000
Mortgage-backed securities
Securities available for sale
Securities available for sale, amortized cost		137,407,000	165,636,000
Unrealized gains		3,594,000	2,156,000
Unrealized losses		120,000	3,151,000
Total securities available for sale, fair value		140,881,000	164,641,000
Obligations of states and political subdivisions
Securities available for sale
Securities available for sale, amortized cost		57,961,000	70,241,000
Unrealized gains		2,844,000	1,562,000
Unrealized losses		12,000	455,000
Total securities available for sale, fair value		60,793,000	71,348,000
Trust preferred securities of financial institutions
Securities available for sale
Securities available for sale, amortized cost		1,000,000
Unrealized gains		18,000
Total securities available for sale, fair value		$ 1,018,000