Loans and Allowance for Loan Losses, Allowance for Loan Losses (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		$ 49,595	$ 44,317
Loans charged off [Abstract]
Total loan charge offs		95	220
Recoveries of loans previously charged off [Abstract]
Total recoveries		141	58
Net loans (recoveries) charged off		(46)	162
(Credit) provision for loan losses		350	2,000
Balance at end of period		49,991	46,155
New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	93	201
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	141	56
Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		2	19
Recoveries of loans previously charged off [Abstract]
Total recoveries		0	2
Commercial [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		4,140	3,999
Loans charged off [Abstract]
Total loan charge offs		0	3
Recoveries of loans previously charged off [Abstract]
Total recoveries		32	2
Net loans (recoveries) charged off		(32)	1
(Credit) provision for loan losses		(120)	(38)
Balance at end of period		4,052	3,960
Commercial [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	0	3
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	32	2
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		44,950	39,748
Loans charged off [Abstract]
Total loan charge offs		86	191
Recoveries of loans previously charged off [Abstract]
Total recoveries		88	53
Net loans (recoveries) charged off		(2)	138
(Credit) provision for loan losses		555	2,033
Balance at end of period		45,507	41,643
Real Estate Mortgage - 1 to 4 Family [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	86	191
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	88	51
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	2
Installment [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		505	570
Loans charged off [Abstract]
Total loan charge offs		9	26
Recoveries of loans previously charged off [Abstract]
Total recoveries		21	3
Net loans (recoveries) charged off		(12)	23
(Credit) provision for loan losses		(85)	5
Balance at end of period		432	552
Installment [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	7	7
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	21	3
Installment [Member] | Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		2	19
Recoveries of loans previously charged off [Abstract]
Total recoveries		$ 0	$ 0

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