Allowance for Loan Losses (Details 1) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	$ 645,062	$ 613,333
Pass [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	573,602	518,577
Special Mention [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	12,655	25,452
Substandard [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	58,805	69,304
Doubtful [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades
Commercial & Agriculture [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	84,848	86,395
Commercial & Agriculture [Member] | Pass [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	74,610	73,011
Commercial & Agriculture [Member] | Special Mention [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	1,901	4,358
Commercial & Agriculture [Member] | Substandard [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	8,337	9,026
Commercial & Agriculture [Member] | Doubtful [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades
Commercial Real Estate [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	405,535	371,852
Commercial Real Estate [Member] | Pass [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	364,004	319,084
Commercial Real Estate [Member] | Special Mention [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	7,625	15,321
Commercial Real Estate [Member] | Substandard [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	33,906	37,447
Commercial Real Estate [Member] | Doubtful [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades
Residential Real Estate [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	111,462	115,412
Residential Real Estate [Member] | Pass [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	94,859	92,577
Residential Real Estate [Member] | Special Mention [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	2,447	5,071
Residential Real Estate [Member] | Substandard [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	14,156	17,764
Residential Real Estate [Member] | Doubtful [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades
Real estate - construction [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	42,250	37,466
Real estate - construction [Member] | Pass [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	39,229	31,697
Real estate - construction [Member] | Special Mention [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	682	702
Real estate - construction [Member] | Substandard [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	2,339	5,067
Real estate - construction [Member] | Doubtful [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades
Consumer [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	967	2,208
Consumer [Member] | Pass [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	900	2,208
Consumer [Member] | Substandard [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades	67
Consumer [Member] | Doubtful [Member]
Credit exposures by internally assigned grades
Credit exposures by internally assigned grades