Loan Portfolio and Allowance for Credit Losses, Allowance for Credit Losses (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		$ 48,578	$ 46,032	$ 46,032
Loans charged off [Abstract]
Total loan charge offs		161	48
Recoveries of loans previously charged off [Abstract]
Total recoveries		203	101
Net loans (recoveries) charged off		(42)	(53)
Provision for credit losses		600	600
Balance at end of period		49,220	46,685	48,578
Provision (benefit) for credit losses		600	300
Credit losses on unfunded commitments		0	300
New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	161	17
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	203	76
Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		0	31
Recoveries of loans previously charged off [Abstract]
Total recoveries		0	25
Commercial [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		2,735	2,596	2,596
Loans charged off [Abstract]
Total loan charge offs		0	0
Recoveries of loans previously charged off [Abstract]
Total recoveries		0	0
Net loans (recoveries) charged off		0	0
Provision for credit losses		7	112
Balance at end of period		2,742	2,708	2,735
Commercial [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	0	0
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	0	0
Commercial [Member] | Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		0	0
Recoveries of loans previously charged off [Abstract]
Total recoveries		0	0
Real Estate Mortgage - 1 to 4 Family [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		45,625	43,271	43,271
Loans charged off [Abstract]
Total loan charge offs		117	0
Recoveries of loans previously charged off [Abstract]
Total recoveries		195	78
Net loans (recoveries) charged off		(78)	(78)
Provision for credit losses		592	417
Balance at end of period		46,295	43,766	45,625
Real Estate Mortgage - 1 to 4 Family [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	117	0
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	195	53
Real Estate Mortgage - 1 to 4 Family [Member] | Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		0	0
Recoveries of loans previously charged off [Abstract]
Total recoveries		0	25
Installment [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		218	165	165
Loans charged off [Abstract]
Total loan charge offs		44	48	176
Recoveries of loans previously charged off [Abstract]
Total recoveries		8	23
Net loans (recoveries) charged off		36	25
Provision for credit losses		1	71
Balance at end of period		183	211	$ 218
Installment [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	44	17
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	8	23
Installment [Member] | Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		0	31
Recoveries of loans previously charged off [Abstract]
Total recoveries		$ 0	$ 0

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