Fair Value (Details 6) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010
ASSETS
Cash and cash equivalents	$ 32,946	$ 39,703	$ 41,176	$ 37,432
Interest bearing time deposits with other banks	225	224
Securities available for sale	719,284	638,107
Trading securities	3,620	3,233
Loans held for sale	3,847	1,442
Net loans	896,568	837,268
FHLB and other equity interests	6,755	6,537
LIABILITIES
Deposits	1,480,270	1,353,851
Subordinated debentures	20,620	20,620
Interest rate swaps	(1,848)
Carrying Amount [Member]
ASSETS
Cash and cash equivalents	32,946	39,703
Interest bearing time deposits with other banks	225	224
Securities available for sale	719,284	638,107
Trading securities	3,620	3,233
Loans held for sale	3,847	1,442
Net loans	896,568	837,268
FHLB and other equity interests	6,755	6,537
Accrued interest receivable	7,357	6,567
LIABILITIES
Deposits	(1,480,270)	(1,353,851)
FHLB and other borrowings	(74,336)	(74,456)
Subordinated debentures	(20,620)	(20,620)
Interest rate swaps	(1,848)	(1,669)
Accrued interest payable	(1,041)	(1,308)
Fair Value [Member]
ASSETS
Cash and cash equivalents	32,946	39,703
Interest bearing time deposits with other banks	225	229
Securities available for sale	719,284	638,107
Trading securities	3,620	3,233
Loans held for sale	3,938	1,470
Net loans	922,833	862,389
FHLB and other equity interests		0
Accrued interest receivable	7,357	6,567
LIABILITIES
Deposits	(1,483,763)	(1,357,415)
FHLB and other borrowings	(77,364)	(83,042)
Subordinated debentures	(11,049)	(10,906)
Interest rate swaps	(1,848)	(1,669)
Accrued interest payable	(1,041)	(1,308)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
ASSETS
Cash and cash equivalents	32,946
Interest bearing time deposits with other banks	0
Securities available for sale	51,173	62,832
Trading securities	3,460	3,078
Loans held for sale	0
Net loans	0
FHLB and other equity interests
Accrued interest receivable	288
LIABILITIES
Deposits	(1,259,828)
FHLB and other borrowings	0
Subordinated debentures	0
Interest rate swaps	0	0
Accrued interest payable	(291)
Significant Other Observable Inputs (Level 2) [Member]
ASSETS
Cash and cash equivalents	0
Interest bearing time deposits with other banks	225
Securities available for sale	665,766	572,875
Trading securities	160	155
Loans held for sale	3,938
Net loans	0
FHLB and other equity interests
Accrued interest receivable	3,753
LIABILITIES
Deposits	(223,935)
FHLB and other borrowings	(77,364)
Subordinated debentures	0
Interest rate swaps	(1,848)
Accrued interest payable	(732)
Significant Unobservable Inputs (Level 3) [Member]
ASSETS
Cash and cash equivalents	0
Interest bearing time deposits with other banks	0
Securities available for sale	2,345	2,400
Trading securities	0	0
Loans held for sale	0
Net loans	922,833
FHLB and other equity interests
Accrued interest receivable	3,316
LIABILITIES
Deposits	0
FHLB and other borrowings	0
Subordinated debentures	(11,049)
Interest rate swaps	0	0
Accrued interest payable	$ (18)