Loans and reserve for credit losses (Details Textual) (USD $)	3 Months Ended	6 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Non-Performing Substandard and Related Performing Loans				$ 110,000,000
Loans Held-for-sale, Mortgages	1,000,000		506,000
Percentage Of Real Estate Related Loans	79.00%
Transfer Of Loans Receivable To Third Party	14,000,000		22,400,000
Impaired loans,Total recorded balance	72,145,000		72,015,000
Increase (Decrease) in Finance Receivables	19,700,000	46,300,000
Current Four Quarters [Member]
Historical Loss Weighted Percentage	50.00%
Next Four Preceding Quarters [Member]
Historical Loss Weighted Percentage	35.00%
Final Four Preceding Quarters [Member]
Historical Loss Weighted Percentage	15.00%
Troubled Debt Restructuring [Member]
Impaired loans,Total recorded balance	50,100,000		43,700,000
Loans and Leases Receivable, Consumer, Allowance	6,800,000		8,300,000
Remaining Commitment To Lend Loan	$ 1,200,000