Securities (Details 2) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Maturities of securities and their weighted average yields
Weighted Average Yield	4.00%
Amortized Cost, Due in one year or less	$ 1,998,000
Amortized Cost, Due from one to five years	3,649,000
Amortized Cost, Due from five to ten years	26,765,000
Amortized Cost, Due after ten years	69,461,000
Amortized Cost	134,664,000	167,158,000
Fair Value, Due in one year or less	2,033,000
Fair Value, Due from one to five years	3,841,000
Fair Value, Due from five to ten years	27,029,000
Fair Value, Due after ten years	70,755,000
Fair Value	138,314,000	172,992,000
Due in one year or less [Member]
Maturities of securities and their weighted average yields
Weighted Average Yield	5.35%
Due from one to five years [Member]
Maturities of securities and their weighted average yields
Weighted Average Yield	5.79%
Due from five to ten years [Member]
Maturities of securities and their weighted average yields
Weighted Average Yield	3.09%
Due After Ten Years [Member]
Maturities of securities and their weighted average yields
Weighted Average Yield	4.22%
Mortgage-backed securities [Member]
Maturities of securities and their weighted average yields
Weighted Average Yield	5.19%
Amortized Cost Basis	20,182,000
Amortized Cost	20,182,000	31,851,000
Fair Value Basis	21,996,000
Fair Value	21,996,000	34,610,000
Michigan Strategic Fund bonds [Member]
Maturities of securities and their weighted average yields
Weighted Average Yield	1.74%
Amortized Cost Basis	11,255,000
Amortized Cost	11,255,000	16,700,000
Fair Value Basis	11,255,000
Fair Value	11,255,000	16,700,000
Mutual funds [Member]
Maturities of securities and their weighted average yields
Weighted Average Yield	3.03%
Amortized Cost Basis	1,354,000
Amortized Cost	1,354,000	1,312,000
Fair Value Basis	1,405,000
Fair Value	$ 1,405,000	$ 1,354,000