Loans Receivable and Allowance for Loan Losses (Details 11) (Mortgage loans (gross), USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 loan	Dec. 31, 2013 loan	Dec. 31, 2012 loan
Information about loans receivable by segment and class modified in troubled debt restructuring
Number of loans	9	37	14
Recorded investment	$ 3,463	$ 9,521	$ 7,854
Residential mortgage loans | Full documentation interest-only loans
Information about loans receivable by segment and class modified in troubled debt restructuring
Number of loans	1	11	1
Recorded investment	621	2,191	165
Residential mortgage loans | Full documentation amortizing loans
Information about loans receivable by segment and class modified in troubled debt restructuring
Number of loans	2	4	2
Recorded investment	319	1,334	643
Residential mortgage loans | Reduced documentation interest-only loans
Information about loans receivable by segment and class modified in troubled debt restructuring
Number of loans	3	17	5
Recorded investment	1,123	4,190	1,829
Residential mortgage loans | Reduced documentation amortizing loans
Information about loans receivable by segment and class modified in troubled debt restructuring
Number of loans		3	4
Recorded investment		788	1,628
Multi-family
Information about loans receivable by segment and class modified in troubled debt restructuring
Number of loans	3	2	2
Recorded investment	$ 1,400	$ 1,018	$ 3,589