Financial Instruments With Off-Balance-Sheet Risk Contractual Amount of Financial Instruments with Credit Risk (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Concentration Risk [Line Items]
Contract or Notional Amount	$ 145,618	$ 139,809
Commitment to originate loans [Member]
Concentration Risk [Line Items]
Contract or Notional Amount	35,689	22,673
Unused lines of credit [Member]
Concentration Risk [Line Items]
Contract or Notional Amount	103,623	109,457
Standby and commercial letters of credit [Member]
Concentration Risk [Line Items]
Contract or Notional Amount	2,308	2,308
Credit card arrangement [Member]
Concentration Risk [Line Items]
Contract or Notional Amount	311	259
MPF credit enhancement obligation, net (See Note 18) (See Note 18)
Concentration Risk [Line Items]
Contract or Notional Amount	687	684
Commitment for purchase of Jericho branch property [Member]
Concentration Risk [Line Items]
Contract or Notional Amount	0	1,220
Commitment for construction of Williston branch [Member]
Concentration Risk [Line Items]
Contract or Notional Amount	0	3,208
Commitment to purchase investment in a real estate limited partnership [Member]
Concentration Risk [Line Items]
Contract or Notional Amount	$ 3,000	$ 0