Loans Receivable - Loan Origination and Risk Management (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, amount	$ 1,146,424	$ 1,111,261
Multi-family mortgage loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, amount	453,720	396,058
Nonresidential Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, amount	243,047	263,567
Commercial leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, amount	$ 203,563	$ 187,112