Loans and Allowance for Loan Losses, Impaired Receivables (Details) - USD ($) $ in Thousands		6 Months Ended		12 Months Ended
		Jun. 30, 2021		Dec. 31, 2020
Impaired loans by loans class [Abstract]
Recorded Investment		$ 20,053		$ 21,581
Unpaid Principal Balance		20,605		22,253
Related Allowance		0		0
Average Recorded Investment		20,725		20,814
New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	16,982		18,331
Unpaid Principal Balance	[1]	17,534		19,003
Related Allowance	[1]	0		0
Average Recorded Investment	[1]	17,777		17,892
Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		3,071		3,250
Unpaid Principal Balance		3,071		3,250
Related Allowance		0		0
Average Recorded Investment		2,948		2,922
Commercial [Member] | Commercial Real Estate [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		601		917
Unpaid Principal Balance		693		1,041
Related Allowance		0		0
Average Recorded Investment		1,234		1,291
Commercial [Member] | Commercial Real Estate [Member] | New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	506		819
Unpaid Principal Balance	[1]	598		943
Related Allowance	[1]	0		0
Average Recorded Investment	[1]	1,129		1,186
Commercial [Member] | Commercial Real Estate [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		95		98
Unpaid Principal Balance		95	[1]	98
Related Allowance		0		0
Average Recorded Investment		105		105
Commercial [Member] | Other [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		69		111
Unpaid Principal Balance		69		111
Related Allowance		0		0
Average Recorded Investment		110		103
Commercial [Member] | Other [Member] | New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	69		111
Unpaid Principal Balance	[1]	69		111
Related Allowance	[1]	0		0
Average Recorded Investment	[1]	110		103
Commercial [Member] | Other [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		0		0
Unpaid Principal Balance		0	[1]	0
Related Allowance		0		0
Average Recorded Investment		0		0
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		16,878		17,932
Unpaid Principal Balance		17,198		18,319
Related Allowance		0		0
Average Recorded Investment		16,633		16,665
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]	14,158		15,024
Unpaid Principal Balance	[1]	14,478		15,411
Related Allowance	[1]	0		0
Average Recorded Investment	[1]	14,050		14,110
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		2,720		2,908
Unpaid Principal Balance		2,720		2,908
Related Allowance		0		0
Average Recorded Investment		2,583		2,555
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		213		219
Unpaid Principal Balance		213		240
Related Allowance		0		0
Average Recorded Investment		249		251
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]	213		219
Unpaid Principal Balance	[1]	213		240
Related Allowance	[1]	0		0
Average Recorded Investment	[1]	235		235
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		14		16
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		2,292		2,402
Unpaid Principal Balance		2,432		2,542
Related Allowance		0		0
Average Recorded Investment		2,499		2,504
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]	2,036		2,158
Unpaid Principal Balance	[1]	2,176		2,298
Related Allowance	[1]	0		0
Average Recorded Investment	[1]	2,253		2,258
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		256		244
Unpaid Principal Balance		256		244
Related Allowance		0		0
Average Recorded Investment		$ 246		$ 246

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