Loan Portfolio and Allowance for Credit Losses, Recorded Investment in Loans by Loan Class (Details) - USD ($) $ in Thousands		Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022
Loans and Leases Receivable [Abstract]
Total loans		$ 4,960,281		$ 4,733,201
Allowance for credit losses on loans		47,226	$ 46,914	46,032	$ 45,517	$ 45,285
Net loans		4,913,055		4,687,169
New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans	[1]	3,246,245		3,219,914
Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		1,714,036		1,513,287
Real Estate Construction Loans [Member]
Loans and Leases Receivable [Abstract]
Total loans		29,300		36,400
Residential Borrowers [Member]
Loans and Leases Receivable [Abstract]
Total loans		7,800		14,100
Commercial Borrowers Residential Purpose [Member]
Loans and Leases Receivable [Abstract]
Total loans		21,500		22,300
Commercial [Member]
Loans and Leases Receivable [Abstract]
Total loans		268,642		231,011
Allowance for credit losses on loans		2,713	2,610	2,596	2,429	2,274
Commercial [Member] | Commercial Real Estate [Member]
Loans and Leases Receivable [Abstract]
Total loans		247,327		209,922
Commercial [Member] | Commercial Real Estate [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans	[1]	208,394		177,371
Commercial [Member] | Commercial Real Estate [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		38,933		32,551
Commercial [Member] | Other [Member]
Loans and Leases Receivable [Abstract]
Total loans		21,315		21,089
Commercial [Member] | Other [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans	[1]	20,947		20,221
Commercial [Member] | Other [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		368		868
Commercial [Member] | PPP Loans [Member]
Loans and Leases Receivable [Abstract]
Total loans		688		1,000
Real Estate Mortgage - 1 to 4 Family [Member]
Loans and Leases Receivable [Abstract]
Total loans		4,675,034		4,489,883
Allowance for credit losses on loans		44,285	44,067	43,271	42,944	42,880
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member]
Loans and Leases Receivable [Abstract]
Total loans		4,284,829		4,146,902
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans	[1]	2,753,008		2,776,989
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		1,531,821		1,369,913
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member]
Loans and Leases Receivable [Abstract]
Total loans		58,177		56,549
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans	[1]	44,873		43,999
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		13,304		12,550
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member]
Loans and Leases Receivable [Abstract]
Total loans		332,028		286,432
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans	[1]	206,806		191,926
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		125,222		94,506
Installment [Member]
Loans and Leases Receivable [Abstract]
Total loans		16,605		12,307
Allowance for credit losses on loans		228	$ 237	165	$ 144	$ 131
Installment [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans	[1]	12,217		9,408
Installment [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		$ 4,388		$ 2,899

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