Loans Receivable, Financial Instruments Whose Contract Amounts Represent Credit Risk (Details) (USD $)			12 Months Ended				12 Months Ended
	Dec. 31, 2012 Standby Letters of Credit [Member]	Dec. 31, 2011 Standby Letters of Credit [Member]	Dec. 31, 2012 Home Equity Lines of Credit [Member]	Dec. 31, 2011 Home Equity Lines of Credit [Member]	Dec. 31, 2012 Unadvanced Construction Commitments [Member]	Dec. 31, 2011 Unadvanced Construction Commitments [Member]	Dec. 31, 2012 Mortgage Loan Commitments [Member]	Dec. 31, 2011 Mortgage Loan Commitments [Member]	Dec. 31, 2012 Lines of Credit [Member]	Dec. 31, 2011 Lines of Credit [Member]	Dec. 31, 2012 Loans Sold with Limited Repurchase Provision [Member]	Dec. 31, 2011 Loans Sold with Limited Repurchase Provision [Member]	Dec. 31, 2010 Loans Sold with Limited Repurchase Provision [Member]
Financial instruments whose contract amount represents credit risk [Abstract]
Off-balance sheet credit risk	$ 16,309,000	$ 15,319,000	$ 13,025,000	$ 14,623,000	$ 15,598,000	$ 18,014,000	$ 13,601,000	$ 1,059,000	$ 31,480,000	$ 31,525,000	$ 31,591,000	$ 17,558,000
Loan expiry period			10 years
Fixed rate loan commitments							13,601,000
Fixed interest rate, minimum (in hundredths)							2.75%
Fixed interest rate, maximum (in hundredths)							4.875%
Floating rate loan commitments							0
Loans receivable held-for-sale, amount											$ 105,674,000	$ 43,403,000	$ 59,113,000