Loans Receivable and Allowance for Loan Losses (Non-Accruing Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 4,362	$ 4,160
Originated loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	2,489	3,126
Originated loans [Member] | Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	788	590
Originated loans [Member] | Commercial and Multi-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	218	761
Originated loans [Member] | Commercial Business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	1,189	1,428
Originated loans [Member] | Home Equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	294	347
Acquired loans recorded at fair value [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	1,873	1,034
Acquired loans recorded at fair value [Member] | Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	602	291
Acquired loans recorded at fair value [Member] | Commercial and Multi-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	758	217
Acquired loans recorded at fair value [Member] | Commercial Business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	513	513
Acquired loans recorded at fair value [Member] | Home Equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans		13
Acquired loans with deteriorated credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 1,100	$ 3,500