Loan Portfolio and Allowance for Credit Losses, Recorded Investment in Loans by Loan Class (Details) - USD ($) $ in Thousands		Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Loans and Leases Receivable [Abstract]
Total loans		$ 4,464,354
Less: Allowance for credit losses on loans		46,178
Net loans		4,418,176
Total loans, net			$ 4,438,779
Less: Allowance for credit losses on loans			44,267	$ 49,991	$ 49,595
Net loans			4,394,512
New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans	[1]	3,123,916
Total loans, net	[1]		3,132,378
Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		1,340,438
Total loans, net			1,306,401
Real Estate Construction Loans [Member]
Loans and Leases Receivable [Abstract]
Total loans		30,400	37,300
Residential Borrowers [Member]
Loans and Leases Receivable [Abstract]
Total loans		10,500	17,900
Commercial Borrowers Residential Purpose [Member]
Loans and Leases Receivable [Abstract]
Total loans		19,900	19,400
Commercial [Member]
Loans and Leases Receivable [Abstract]
Total loans		192,408
Less: Allowance for credit losses on loans		2,177
Total loans, net			200,200
Less: Allowance for credit losses on loans			3,135	4,052	4,140
Commercial [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[2]		177,952
Commercial [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net			22,248
Commercial [Member] | Commercial Real Estate [Member]
Loans and Leases Receivable [Abstract]
Total loans		171,230
Total loans, net			168,716
Commercial [Member] | Commercial Real Estate [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans	[1]	147,295
Total loans, net	[1],[2]		147,063
Commercial [Member] | Commercial Real Estate [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		23,935
Total loans, net			21,653
Commercial [Member] | Other [Member]
Loans and Leases Receivable [Abstract]
Total loans		21,178
Total loans, net			31,484
Commercial [Member] | Other [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans	[1]	20,198
Total loans, net	[1],[2]		30,889
Commercial [Member] | Other [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		980
Total loans, net			595
Commercial [Member] | PPP Loans [Member]
Loans and Leases Receivable [Abstract]
Total loans		3,000	10,000
Real Estate Mortgage - 1 to 4 Family [Member]
Loans and Leases Receivable [Abstract]
Total loans		4,262,551
Less: Allowance for credit losses on loans		43,931
Total loans, net			4,229,163
Less: Allowance for credit losses on loans			40,689	45,507	44,950
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member]
Loans and Leases Receivable [Abstract]
Total loans		3,965,962
Total loans, net			3,936,302
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]	2,729,257
Total loans, net	[1]		2,723,734
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		1,236,705
Total loans, net			1,212,568
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member]
Loans and Leases Receivable [Abstract]
Total loans		60,472
Total loans, net			61,885
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]	47,043
Total loans, net	[1]		48,190
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		13,429
Total loans, net			13,695
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member]
Loans and Leases Receivable [Abstract]
Total loans		236,117
Total loans, net			230,976
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]	172,854
Total loans, net	[1]		175,134
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		63,263
Total loans, net			55,842
Installment [Member]
Loans and Leases Receivable [Abstract]
Total loans		9,395
Less: Allowance for credit losses on loans		70
Total loans, net			9,416
Less: Allowance for credit losses on loans			443	$ 432	$ 505
Installment [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans	[1]	7,269
Total loans, net	[1]		7,368
Installment [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans		$ 2,126
Total loans, net			$ 2,048

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

[2] Includes New York, New Jersey and Massachusetts.