Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair Value of Financial Instruments
Total securities available-for-sale	$ 401,690	$ 336,300
Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	401,690	336,300
Residential mortgage-backed securities
Fair Value of Financial Instruments
Total securities available-for-sale	310,534	237,421
Residential mortgage-backed securities | Recurring basis
Fair Value of Financial Instruments
Percentage of debt securities comprising available-for-sale portfolio	77.00%	71.00%
Available-for-sale residential mortgage-backed securities portfolio which are GSE securities (as a percent)	98.00%	95.00%
GSE issuance REMICs and CMOs
Fair Value of Financial Instruments
Total securities available-for-sale	286,074	204,827
GSE issuance REMICs and CMOs | Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	286,074	204,827
Non-GSE issuance REMICs and CMOs
Fair Value of Financial Instruments
Total securities available-for-sale	7,572	11,219
Non-GSE issuance REMICs and CMOs | Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	7,572	11,219
GSE pass-through certificates
Fair Value of Financial Instruments
Total securities available-for-sale	16,888	21,375
GSE pass-through certificates | Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	16,888	21,375
Obligations of GSEs
Fair Value of Financial Instruments
Total securities available-for-sale	91,153	98,879
Obligations of GSEs | Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	91,153	98,879
Percentage of debt securities comprising available-for-sale portfolio	23.00%	29.00%
Fannie Mae stock
Fair Value of Financial Instruments
Total securities available-for-sale	3
Fannie Mae stock | Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	3
Level 1 | Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	3
Level 1 | Fannie Mae stock | Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	3
Level 2 | Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	401,687	336,300
Level 2 | GSE issuance REMICs and CMOs | Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	286,074	204,827
Level 2 | Non-GSE issuance REMICs and CMOs | Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	7,572	11,219
Level 2 | GSE pass-through certificates | Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	16,888	21,375
Level 2 | Obligations of GSEs | Recurring basis
Fair Value of Financial Instruments
Total securities available-for-sale	$ 91,153	$ 98,879