Loans and Allowance for Loan Losses, Allowance for Loan Losses (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		$ 49,991	$ 46,155	$ 49,595	$ 44,317
Loans charged off [Abstract]
Total loan charge offs		21	71	116	291
Recoveries of loans previously charged off [Abstract]
Total recoveries		185	60	326	118
Net loans (recoveries) charged off		(164)	11	(210)	173
(Credit) provision for loan losses		0	2,000	350	4,000
Balance at end of period		50,155	48,144	50,155	48,144
New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	21	71	114	272
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	184	60	325	116
Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		0	0	2	19
Recoveries of loans previously charged off [Abstract]
Total recoveries		1	0	1	2
Commercial [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		4,052	3,960	4,140	3,999
Loans charged off [Abstract]
Total loan charge offs		0	0	0	3
Recoveries of loans previously charged off [Abstract]
Total recoveries		0	6	32	8
Net loans (recoveries) charged off		0	(6)	(32)	(5)
(Credit) provision for loan losses		54	400	(66)	362
Balance at end of period		4,106	4,366	4,106	4,366
Commercial [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	0	0	0	3
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	0	6	32	8
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		45,507	41,643	44,950	39,748
Loans charged off [Abstract]
Total loan charge offs		20	22	106	213
Recoveries of loans previously charged off [Abstract]
Total recoveries		157	49	245	102
Net loans (recoveries) charged off		(137)	(27)	(139)	111
(Credit) provision for loan losses		(27)	1,604	528	3,637
Balance at end of period		45,617	43,274	45,617	43,274
Real Estate Mortgage - 1 to 4 Family [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	20	22	106	213
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	156	49	244	100
Real Estate Mortgage - 1 to 4 Family [Member] | Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		0	0	0	0
Recoveries of loans previously charged off [Abstract]
Total recoveries		1	0	1	2
Installment [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		432	552	505	570
Loans charged off [Abstract]
Total loan charge offs		1	49	10	75
Recoveries of loans previously charged off [Abstract]
Total recoveries		28	5	49	8
Net loans (recoveries) charged off		(27)	44	(39)	67
(Credit) provision for loan losses		(27)	(4)	(112)	1
Balance at end of period		432	504	432	504
Installment [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	1	49	8	56
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	28	5	49	8
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.