Allowance for Loan Losses (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance at beginning of period			$ (439)
Allowance at end of period	(260)		(439)
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance at beginning of period	(150)	(2,268)
Provision for loan losses	0	60
Credit losses, net of recoveries	5	987
Allowance at end of period	(145)	(1,341)
Unpaid principal balance of impaired securitized loans	0		1,814
Basis adjustments related to impaired securitized loans	0		0
Amortized cost basis of impaired securitized loans	0		1,814
Interest income recognized on impaired securitized loans	0	25
Single-family [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance at beginning of period	(289)	(231)
Provision for loan losses	261	0
Credit losses, net of recoveries	435	0
Allowance at end of period	(115)	(231)
Unpaid principal balance of impaired securitized loans	4,171		3,029
Basis adjustments related to impaired securitized loans	62		59
Amortized cost basis of impaired securitized loans	4,233		3,088
Interest income recognized on impaired securitized loans	$ 61	$ 40