Commitments and Off-Balance Sheet Risk (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Summary of contractual amounts of financial instruments with off-balance sheet risk
Contractual amounts of financial instruments with off-balance sheet	$ 294,238,000	$ 254,130,000
Commercial unused lines of credit [Member]
Summary of contractual amounts of financial instruments with off-balance sheet risk
Contractual amounts of financial instruments with off-balance sheet	172,367,000	171,683,000
Unused lines of credit secured by 1 - 4 family residential properties [Member]
Summary of contractual amounts of financial instruments with off-balance sheet risk
Contractual amounts of financial instruments with off-balance sheet	24,611,000	24,663,000
Credit card unused lines of credit [Member]
Summary of contractual amounts of financial instruments with off-balance sheet risk
Contractual amounts of financial instruments with off-balance sheet	7,924,000	7,565,000
Other consumer unused lines of credit [Member]
Summary of contractual amounts of financial instruments with off-balance sheet risk
Contractual amounts of financial instruments with off-balance sheet	4,251,000	3,367,000
Commitments to extend credit [Member]
Summary of contractual amounts of financial instruments with off-balance sheet risk
Contractual amounts of financial instruments with off-balance sheet	74,263,000	30,929,000
Standby letters of credit [Member]
Summary of contractual amounts of financial instruments with off-balance sheet risk
Contractual amounts of financial instruments with off-balance sheet	$ 10,822,000	$ 15,923,000