Loans Receivable and Allowance for Loan Losses (Delinquency Status of Total Loans) (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	$ 31,062,000	$ 30,879,000
Current	2,302,201,000	2,299,139,000
Financing Receivable, Net, Total	2,333,263,000	2,330,018,000
Loans Receivable >90 Days and Accruing	0	333,000
30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	17,563,000	20,847,000
60 to 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	5,602,000	4,178,000
Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	7,897,000	5,854,000
Originated loans [Member] \| Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	1,163,000	1,437,000
Current	233,212,000	242,932,000
Financing Receivable, Net, Total	234,375,000	244,369,000
Loans Receivable >90 Days and Accruing		125,000
Originated loans [Member] \| Residential [Member] \| 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	936,000	507,000
Originated loans [Member] \| Residential [Member] \| 60 to 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due		266,000
Originated loans [Member] \| Residential [Member] \| Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	227,000	664,000
Originated loans [Member] \| Commercial & Multi-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	20,005,000	20,240,000
Current	1,680,108,000	1,670,596,000
Financing Receivable, Net, Total	1,700,113,000	1,690,836,000
Loans Receivable >90 Days and Accruing
Originated loans [Member] \| Commercial & Multi-family [Member] \| 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	13,148,000	15,910,000
Originated loans [Member] \| Commercial & Multi-family [Member] \| 60 to 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	4,410,000	2,996,000
Originated loans [Member] \| Commercial & Multi-family [Member] \| Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	2,447,000	1,334,000
Originated loans [Member] \| Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	2,787,000
Current	164,437,000	155,967,000
Financing Receivable, Net, Total	167,224,000	155,967,000
Loans Receivable >90 Days and Accruing
Originated loans [Member] \| Construction [Member] \| 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	2,787,000
Originated loans [Member] \| Commercial Business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	6,406,000	8,147,000
Current	170,934,000	176,210,000
Financing Receivable, Net, Total	177,340,000	184,357,000
Loans Receivable >90 Days and Accruing		133,000
Originated loans [Member] \| Commercial Business [Member] \| 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	457,000	3,889,000
Originated loans [Member] \| Commercial Business [Member] \| 60 to 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	1,153,000	904,000
Originated loans [Member] \| Commercial Business [Member] \| Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	4,796,000	3,354,000
Originated loans [Member] \| Home Equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	701,000	1,055,000
Current	52,659,000	52,612,000
Financing Receivable, Net, Total	53,360,000	53,667,000
Loans Receivable >90 Days and Accruing		75,000
Originated loans [Member] \| Home Equity [Member] \| 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	235,000	541,000
Originated loans [Member] \| Home Equity [Member] \| 60 to 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	39,000	12,000
Originated loans [Member] \| Home Equity [Member] \| Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	427,000	502,000
Originated loans [Member] \| Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	851,000	822,000
Financing Receivable, Net, Total	851,000	822,000
Loans Receivable >90 Days and Accruing