Loans and Allowance for Loan Losses, Impaired Receivables (Details) - USD ($) $ in Thousands		6 Months Ended	12 Months Ended
		Jun. 30, 2019	Dec. 31, 2018
Impaired loans by loans class [Abstract]
Recorded Investment		$ 20,780	$ 22,288
Unpaid Principal Balance		21,403	23,309
Related Allowance		0	0
Average Recorded Investment		21,692	23,161
New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	18,325	19,546
Unpaid Principal Balance	[1]	18,948	20,461
Related Allowance	[1]	0	0
Average Recorded Investment	[1]	19,066	20,237
Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		2,455	2,742
Unpaid Principal Balance		2,455	2,848
Related Allowance		0	0
Average Recorded Investment		2,626	2,924
Commercial [Member] | Commercial Real Estate [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		1,661	1,386
Unpaid Principal Balance		1,831	1,556
Related Allowance		0	0
Average Recorded Investment		1,531	1,560
Commercial [Member] | Commercial Real Estate [Member] | New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	1,552	1,274
Unpaid Principal Balance	[1]	1,722	1,444
Related Allowance	[1]	0	0
Average Recorded Investment	[1]	1,419	1,503
Commercial [Member] | Commercial Real Estate [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		109	112
Unpaid Principal Balance		109	112
Related Allowance		0	0
Average Recorded Investment		112	57
Commercial [Member] | Other [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		35	38
Unpaid Principal Balance		35	88
Related Allowance		0	0
Average Recorded Investment		106	123
Commercial [Member] | Other [Member] | New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	35	38
Unpaid Principal Balance	[1]	35	88
Related Allowance	[1]	0	0
Average Recorded Investment	[1]	106	123
Commercial [Member] | Other [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		0	0
Unpaid Principal Balance		0	0
Related Allowance		0	0
Average Recorded Investment		0	0
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		16,114	17,503
Unpaid Principal Balance		16,407	18,060
Related Allowance		0	0
Average Recorded Investment		16,962	18,032
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	14,100	15,210
Unpaid Principal Balance	[1]	14,393	15,661
Related Allowance	[1]	0	0
Average Recorded Investment	[1]	14,784	15,577
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		2,014	2,293
Unpaid Principal Balance		2,014	2,399
Related Allowance		0	0
Average Recorded Investment		2,178	2,455
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		324	336
Unpaid Principal Balance		344	356
Related Allowance		0	0
Average Recorded Investment		333	348
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	243	252
Unpaid Principal Balance	[1]	263	272
Related Allowance	[1]	0	0
Average Recorded Investment	[1]	250	262
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		81	84
Unpaid Principal Balance		81	84
Related Allowance		0	0
Average Recorded Investment		83	86
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		2,646	3,025
Unpaid Principal Balance		2,786	3,249
Related Allowance		0	0
Average Recorded Investment		2,760	3,098
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | New York and Other States [Member]
Impaired loans by loans class [Abstract]
Recorded Investment	[1]	2,395	2,772
Unpaid Principal Balance	[1]	2,535	2,996
Related Allowance	[1]	0	0
Average Recorded Investment	[1]	2,507	2,772
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | Florida [Member]
Impaired loans by loans class [Abstract]
Recorded Investment		251	253
Unpaid Principal Balance		251	253
Related Allowance		0	0
Average Recorded Investment		$ 253	$ 326

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