Loans and Allowance for Loan Losses, Allowance for Loan Losses (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		$ 50,155	$ 48,144	$ 49,595	$ 44,317
Loans charged off [Abstract]
Total loan charge offs		120	85	236	376
Recoveries of loans previously charged off [Abstract]
Total recoveries		115	64	441	182
Net loans (recoveries) charged off		5	21	(205)	194
(Credit) provision for loan losses		(2,800)	1,000	(2,450)	5,000
Balance at end of period		47,350	49,123	47,350	49,123
New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	119	85	233	357
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	114	64	439	180
Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		1	0	3	19
Recoveries of loans previously charged off [Abstract]
Total recoveries		1	0	2	2
Commercial [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		4,106	4,366	4,140	3,999
Loans charged off [Abstract]
Total loan charge offs		30	0	30	3
Recoveries of loans previously charged off [Abstract]
Total recoveries		0	1	32	9
Net loans (recoveries) charged off		30	(1)	(2)	(6)
(Credit) provision for loan losses		(823)	(100)	(889)	262
Balance at end of period		3,253	4,267	3,253	4,267
Commercial [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	30	0	30	3
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	0	1	32	9
Commercial [Member] | Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		0	0	0	0
Recoveries of loans previously charged off [Abstract]
Total recoveries		0	0	0	0
Real Estate Mortgage - 1 to 4 Family [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		45,617	43,274	44,950	39,748
Loans charged off [Abstract]
Total loan charge offs		73	64	179	277
Recoveries of loans previously charged off [Abstract]
Total recoveries		112	60	357	162
Net loans (recoveries) charged off		(39)	4	(178)	115
(Credit) provision for loan losses		(2,003)	1,053	(1,475)	4,690
Balance at end of period		43,653	44,323	43,653	44,323
Real Estate Mortgage - 1 to 4 Family [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	72	64	178	277
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	111	60	355	160
Real Estate Mortgage - 1 to 4 Family [Member] | Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		1	0	1	0
Recoveries of loans previously charged off [Abstract]
Total recoveries		1	0	2	2
Installment [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		432	504	505	570
Loans charged off [Abstract]
Total loan charge offs		17	21	27	96
Recoveries of loans previously charged off [Abstract]
Total recoveries		3	3	52	11
Net loans (recoveries) charged off		14	18	(25)	85
(Credit) provision for loan losses		26	47	(86)	48
Balance at end of period		444	533	444	533
Installment [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	17	21	25	77
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	3	3	52	11
Installment [Member] | Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		0	0	2	19
Recoveries of loans previously charged off [Abstract]
Total recoveries		$ 0	$ 0	$ 0	$ 0

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