Loans and Allowance for Loan Losses, Impaired Receivables (Details) - USD ($) $ in Thousands		6 Months Ended	12 Months Ended
		Jun. 30, 2020	Dec. 31, 2019
Impaired loans by loans class [Abstract]
Recorded Investment		$ 20,382	$ 20,976
Unpaid Principal Balance		21,042	21,578
Related Allowance		0	0
Average Recorded Investment		20,644	20,963
New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	16,996	18,141
Unpaid Principal Balance	[1]	17,656	18,743
Related Allowance	[1]	0	0
Average Recorded Investment	[1]	17,622	18,296
Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		3,386	2,835
Unpaid Principal Balance		3,386	2,835
Related Allowance		0	0
Average Recorded Investment		3,022	2,667
Commercial [Member] | Commercial Real Estate [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		900	1,322
Unpaid Principal Balance		1,024	1,464
Related Allowance		0	0
Average Recorded Investment		1,162	1,467
Commercial [Member] | Commercial Real Estate [Member] | New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	798	1,217
Unpaid Principal Balance	[1]	922	1,359
Related Allowance	[1]	0	0
Average Recorded Investment	[1]	1,057	1,385
Commercial [Member] | Commercial Real Estate [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		102	105
Unpaid Principal Balance		102	105
Related Allowance		0	0
Average Recorded Investment		105	82
Commercial [Member] | Other [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		145	115
Unpaid Principal Balance		145	115
Related Allowance		0	0
Average Recorded Investment		118	64
Commercial [Member] | Other [Member] | New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	145	115
Unpaid Principal Balance	[1]	145	115
Related Allowance	[1]	0	0
Average Recorded Investment	[1]	118	38
Commercial [Member] | Other [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		0	0
Unpaid Principal Balance		0	0
Related Allowance		0	0
Average Recorded Investment		0	26
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		16,630	16,900
Unpaid Principal Balance		17,006	17,200
Related Allowance		0	0
Average Recorded Investment		16,630	16,617
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	13,590	14,414
Unpaid Principal Balance	[1]	13,966	14,714
Related Allowance	[1]	0	0
Average Recorded Investment	[1]	13,968	14,358
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		3,040	2,486
Unpaid Principal Balance		3,040	2,486
Related Allowance		0	0
Average Recorded Investment		2,662	2,259
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		227	235
Unpaid Principal Balance		247	255
Related Allowance		0	0
Average Recorded Investment		243	292
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	227	235
Unpaid Principal Balance	[1]	247	255
Related Allowance	[1]	0	0
Average Recorded Investment	[1]	233	241
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		0	0
Unpaid Principal Balance		0	0
Related Allowance		0	0
Average Recorded Investment		10	51
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		2,480	2,404
Unpaid Principal Balance		2,620	2,544
Related Allowance		0	0
Average Recorded Investment		2,491	2,523
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	2,236	2,160
Unpaid Principal Balance	[1]	2,376	2,300
Related Allowance	[1]	0	0
Average Recorded Investment	[1]	2,246	2,274
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		244	244
Unpaid Principal Balance		244	244
Related Allowance		0	0
Average Recorded Investment		$ 245	$ 249

[1] Includes New York, New Jersey, Vermont and Massachusetts.