Loan Portfolio and Allowance for Credit Losses, Performance of Loans Modified to Borrowers Experiencing Financial Difficulty (Details) - USD ($) $ in Thousands		Sep. 30, 2024	Sep. 30, 2023
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		$ 685	$ 880
New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	512	540
Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		173	340
30 - 59 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	139
30 - 59 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	139
30 - 59 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
60 - 89 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
60 - 89 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
90+ Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
90+ Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Current [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		685	741
Current [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	512	401
Current [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		173	340
Commercial [Member] | Commercial Real Estate [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Commercial Real Estate [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Commercial [Member] | Commercial Real Estate [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Commercial Real Estate [Member] | 30 - 59 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Commercial Real Estate [Member] | 30 - 59 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Commercial [Member] | Commercial Real Estate [Member] | 30 - 59 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Commercial Real Estate [Member] | 60 - 89 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Commercial Real Estate [Member] | 60 - 89 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Commercial [Member] | Commercial Real Estate [Member] | 60 - 89 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Commercial Real Estate [Member] | 90+ Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Commercial Real Estate [Member] | 90+ Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Commercial [Member] | Commercial Real Estate [Member] | 90+ Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Commercial Real Estate [Member] | Current [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Commercial Real Estate [Member] | Current [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Commercial [Member] | Commercial Real Estate [Member] | Current [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Other [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Other [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Commercial [Member] | Other [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Other [Member] | 30 - 59 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Other [Member] | 30 - 59 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Commercial [Member] | Other [Member] | 30 - 59 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Other [Member] | 60 - 89 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Other [Member] | 60 - 89 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Commercial [Member] | Other [Member] | 60 - 89 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Other [Member] | 90+ Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Other [Member] | 90+ Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Commercial [Member] | Other [Member] | 90+ Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Other [Member] | Current [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Commercial [Member] | Other [Member] | Current [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Commercial [Member] | Other [Member] | Current [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		354	830
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	270	490
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		84	340
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 30 - 59 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	139
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 30 - 59 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	139
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 30 - 59 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 60 - 89 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 60 - 89 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 60 - 89 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 90+ Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 90+ Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 90+ Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | Current [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		354	691
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | Current [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	270	351
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | Current [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		84	340
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		89	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		89	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 30 - 59 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 30 - 59 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 30 - 59 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 60 - 89 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 60 - 89 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 60 - 89 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 90+ Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 90+ Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 90+ Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | Current [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		89	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | Current [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | Current [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		89	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		242	50
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	242	50
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 30 - 59 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 30 - 59 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 30 - 59 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 60 - 89 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 60 - 89 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 60 - 89 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 90+ Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 90+ Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 90+ Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | Current [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		242	50
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | Current [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	242	50
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | Current [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Installment [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Installment [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Installment [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Installment [Member] | 30 - 59 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Installment [Member] | 30 - 59 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Installment [Member] | 30 - 59 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Installment [Member] | 60 - 89 Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Installment [Member] | 60 - 89 Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Installment [Member] | 60 - 89 Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Installment [Member] | 90+ Days Past Due [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Installment [Member] | 90+ Days Past Due [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Installment [Member] | 90+ Days Past Due [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Installment [Member] | Current [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		0	0
Installment [Member] | Current [Member] | New York and Other States [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans	[1]	0	0
Installment [Member] | Current [Member] | Florida [Member]
Performance of Loans Modified to Borrowers Experiencing Financial Difficulty [Abstract]
Performance of modified loans		$ 0	$ 0

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