Loans Receivable and Allowance For Loan Losses - Narrative (Details)	Dec. 31, 2019 division segment item
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loan portfolio segments | segment	3
Number of warehouse lending divisions | division	2
Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of units in real estate property | item	5