Loans and Allowance for Loan Losses, Allowance for Loan Losses (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		$ 44,766	$ 44,170
Loans charged off [Abstract]
Total loan charge offs		488	205
Recoveries of loans previously charged off [Abstract]
Total recoveries		93	115
Net loans charged off (recoveries)		395	90
Provision for loan losses		300	300
Balance at end of period		44,671	44,379
New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	428	202
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	83	115
Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		60	3
Recoveries of loans previously charged off [Abstract]
Total recoveries		10	0
Commercial [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		4,048	4,324
Loans charged off [Abstract]
Total loan charge offs		7	0
Recoveries of loans previously charged off [Abstract]
Total recoveries		3	6
Net loans charged off (recoveries)		4	(6)
Provision for loan losses		(310)	(75)
Balance at end of period		3,734	4,255
Commercial [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	7	0
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	3	6
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		39,772	39,077
Loans charged off [Abstract]
Total loan charge offs		421	131
Recoveries of loans previously charged off [Abstract]
Total recoveries		84	103
Net loans charged off (recoveries)		337	28
Provision for loan losses		550	310
Balance at end of period		39,985	39,359
Real Estate Mortgage - 1 to 4 Family [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	392	131
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	74	103
Real Estate Mortgage - 1 to 4 Family [Member] | Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		29	0
Recoveries of loans previously charged off [Abstract]
Total recoveries		10	0
Installment [Member]
Allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period		946	769
Loans charged off [Abstract]
Total loan charge offs		60	74
Recoveries of loans previously charged off [Abstract]
Total recoveries		6	6
Net loans charged off (recoveries)		54	68
Provision for loan losses		60	64
Balance at end of period		952	765
Installment [Member] | New York and Other States [Member]
Loans charged off [Abstract]
Total loan charge offs	[1]	29	71
Recoveries of loans previously charged off [Abstract]
Total recoveries	[1]	6	6
Installment [Member] | Florida [Member]
Loans charged off [Abstract]
Total loan charge offs		31	3
Recoveries of loans previously charged off [Abstract]
Total recoveries		$ 0	$ 0

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