Loans and Allowance for Loan Losses, Allowance for Loan Losses (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		$ 44,671	$ 44,379	$ 44,766	$ 44,170
Loans charged off [Abstract]
Total loan charge offs		254	283	742	488
Recoveries of loans previously charged off [Abstract]
Total recoveries		289	107	382	221
Net loans (recoveries) charged off		(35)	176	360	267
(Recoveries) provision for loan losses		(341)	300	(41)	600
Balance at end of period		44,365	44,503	44,365	44,503
New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	254	280	682	482
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	264	104	347	218
Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		0	3	60	6
Recoveries of loans previously charged off [Abstract]
Total recoveries		25	3	35	3
Commercial [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		3,734	4,255	4,048	4,324
Loans charged off [Abstract]
Total loan charge offs		0	0	7	0
Recoveries of loans previously charged off [Abstract]
Total recoveries		1	1	4	7
Net loans (recoveries) charged off		(1)	(1)	3	(7)
(Recoveries) provision for loan losses		178	(61)	(132)	(136)
Balance at end of period		3,913	4,195	3,913	4,195
Commercial [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	0	0	7	0
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	1	1	4	7
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		39,985	39,359	39,772	39,077
Loans charged off [Abstract]
Total loan charge offs		205	239	626	370
Recoveries of loans previously charged off [Abstract]
Total recoveries		284	89	368	192
Net loans (recoveries) charged off		(79)	150	258	178
(Recoveries) provision for loan losses		(101)	262	449	572
Balance at end of period		39,963	39,471	39,963	39,471
Real Estate Mortgage - 1 to 4 Family [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	205	239	597	370
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	259	89	333	192
Real Estate Mortgage - 1 to 4 Family [Member] | Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		0	0	29	0
Recoveries of loans previously charged off [Abstract]
Total recoveries		25	0	35	0
Installment [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		952	765	946	769
Loans charged off [Abstract]
Total loan charge offs		49	44	109	118
Recoveries of loans previously charged off [Abstract]
Total recoveries		4	17	10	22
Net loans (recoveries) charged off		45	27	99	96
(Recoveries) provision for loan losses		(418)	99	(358)	164
Balance at end of period		489	837	489	837
Installment [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	49	41	78	112
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	4	14	10	19
Installment [Member] | Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		0	3	31	6
Recoveries of loans previously charged off [Abstract]
Total recoveries		$ 0	$ 3	$ 0	$ 3

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