Loans and Allowance for Loan Losses - Amortized Cost of Collateral (Details) $ in Thousands	Sep. 30, 2020 USD ($)
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral Type	$ 16,394
Business Assets
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral Type	8,483
Multi-family Residential Portfolio Segment [Member] | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral Type	2,723
Commercial Real Estate Portfolio Segment [Member] | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral Type	6,045
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral Type	1,704
One-To-Four Family - Residential Portfolio Segment [Member] | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral Type	5,922
Small Business Administration Portfolio Segment [Member] | Business Assets
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral Type	1,169
Commercial Business and Other Portfolio Segment [Member] | Business Assets
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral Type	4,996
Taxi Medallion Portfolio Segment [Member] | Business Assets
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral Type	$ 2,318