Loan Portfolio and Allowance for Credit Losses - Performance of Loans Modified to Borrowers Experiencing Financial Difficulty (Details) - USD ($) $ in Thousands		Mar. 31, 2026	Mar. 31, 2025
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		$ 1,338	$ 870
Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
New York and Other States [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	316	870
New York and Other States [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
Florida [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		1,022	0
Florida [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Commercial Real Estate [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Commercial Real Estate [Member] | New York and Other States [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
Commercial Real Estate [Member] | Florida [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Other [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Other [Member] | New York and Other States [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
Other [Member] | Florida [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
First Mortgages [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		1,338	339
First Mortgages [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	316	339
First Mortgages [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		1,022	0
Home Equity Loans [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	106
Home Equity Loans [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	106
Home Equity Loans [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Home Equity Lines of Credit [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	425
Home Equity Lines of Credit [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	425
Home Equity Lines of Credit [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Current [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		1,100	487
Current [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Current [Member] | New York and Other States [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	78	487
Current [Member] | New York and Other States [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
Current [Member] | Florida [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		1,022	0
Current [Member] | Florida [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Current [Member] | Commercial Real Estate [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Current [Member] | Commercial Real Estate [Member] | New York and Other States [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
Current [Member] | Commercial Real Estate [Member] | Florida [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Current [Member] | Other [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Current [Member] | Other [Member] | New York and Other States [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
Current [Member] | Other [Member] | Florida [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Current [Member] | First Mortgages [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		1,100	78
Current [Member] | First Mortgages [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	78	78
Current [Member] | First Mortgages [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		1,022	0
Current [Member] | Home Equity Loans [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	106
Current [Member] | Home Equity Loans [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	106
Current [Member] | Home Equity Loans [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
Current [Member] | Home Equity Lines of Credit [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	303
Current [Member] | Home Equity Lines of Credit [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	303
Current [Member] | Home Equity Lines of Credit [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
30 - 59 Days Past Due [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	181
30 - 59 Days Past Due [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
30 - 59 Days Past Due [Member] | New York and Other States [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	181
30 - 59 Days Past Due [Member] | New York and Other States [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
30 - 59 Days Past Due [Member] | Florida [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
30 - 59 Days Past Due [Member] | Florida [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
30 - 59 Days Past Due [Member] | Commercial Real Estate [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
30 - 59 Days Past Due [Member] | Commercial Real Estate [Member] | New York and Other States [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
30 - 59 Days Past Due [Member] | Commercial Real Estate [Member] | Florida [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
30 - 59 Days Past Due [Member] | Other [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
30 - 59 Days Past Due [Member] | Other [Member] | New York and Other States [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
30 - 59 Days Past Due [Member] | Other [Member] | Florida [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
30 - 59 Days Past Due [Member] | First Mortgages [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	181
30 - 59 Days Past Due [Member] | First Mortgages [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	181
30 - 59 Days Past Due [Member] | First Mortgages [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
30 - 59 Days Past Due [Member] | Home Equity Loans [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
30 - 59 Days Past Due [Member] | Home Equity Loans [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
30 - 59 Days Past Due [Member] | Home Equity Loans [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
30 - 59 Days Past Due [Member] | Home Equity Lines of Credit [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
30 - 59 Days Past Due [Member] | Home Equity Lines of Credit [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
30 - 59 Days Past Due [Member] | Home Equity Lines of Credit [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	122
60 - 89 Days Past Due [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member] | New York and Other States [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	122
60 - 89 Days Past Due [Member] | New York and Other States [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
60 - 89 Days Past Due [Member] | Florida [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member] | Florida [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member] | Commercial Real Estate [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member] | Commercial Real Estate [Member] | New York and Other States [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
60 - 89 Days Past Due [Member] | Commercial Real Estate [Member] | Florida [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member] | Other [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member] | Other [Member] | New York and Other States [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
60 - 89 Days Past Due [Member] | Other [Member] | Florida [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member] | First Mortgages [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member] | First Mortgages [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
60 - 89 Days Past Due [Member] | First Mortgages [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member] | Home Equity Loans [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member] | Home Equity Loans [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
60 - 89 Days Past Due [Member] | Home Equity Loans [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member] | Home Equity Lines of Credit [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	122
60 - 89 Days Past Due [Member] | Home Equity Lines of Credit [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	122
60 - 89 Days Past Due [Member] | Home Equity Lines of Credit [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		238	80
90+ Days Past Due [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member] | New York and Other States [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	238	80
90+ Days Past Due [Member] | New York and Other States [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
90+ Days Past Due [Member] | Florida [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member] | Florida [Member] | Installment [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member] | Commercial Real Estate [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member] | Commercial Real Estate [Member] | New York and Other States [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
90+ Days Past Due [Member] | Commercial Real Estate [Member] | Florida [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member] | Other [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member] | Other [Member] | New York and Other States [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
90+ Days Past Due [Member] | Other [Member] | Florida [Member] | Commercial [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member] | First Mortgages [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		238	80
90+ Days Past Due [Member] | First Mortgages [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	238	80
90+ Days Past Due [Member] | First Mortgages [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member] | Home Equity Loans [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member] | Home Equity Loans [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
90+ Days Past Due [Member] | Home Equity Loans [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member] | Home Equity Lines of Credit [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member] | Home Equity Lines of Credit [Member] | New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans	[1]	0	0
90+ Days Past Due [Member] | Home Equity Lines of Credit [Member] | Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member]
Loan Portfolio and Allowance for Credit Losses [Abstract]
Performance of modified loans		$ 0	$ 0

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