Loan Portfolio and Allowance for Credit Losses, Risk Category of Loans (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Credit Risk Profile, Segregated by Class [Abstract]
Total loans		$ 4,629,491		$ 4,629,491
Total loans, net						$ 4,438,779
Current-period Gross writeoffs		47	$ 120	118	$ 236
Impaired loans included in classified loans						226
New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans	[1]	3,187,037		3,187,037
Total loans, net	[1]					3,132,378
Current-period Gross writeoffs	[1]	47	119	118	233
Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans		1,442,454		1,442,454
Total loans, net						1,306,401
Current-period Gross writeoffs		0	1	0	3
Commercial [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans		217,120		217,120
Total loans, net						200,200
Current-period Gross writeoffs		0	30	40	30
Commercial [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						177,952
Current-period Gross writeoffs	[1]	0	30	40	30
Commercial [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						22,248
Current-period Gross writeoffs		0	0	0	0
Commercial [Member] | Pass [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						197,934
Commercial [Member] | Pass [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						176,226
Commercial [Member] | Pass [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						21,708
Commercial [Member] | Classified [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						2,266
Commercial [Member] | Classified [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						1,726
Commercial [Member] | Classified [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						540
Commercial [Member] | Commercial Real Estate [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		58,331		58,331
2021		30,325		30,325
2020		18,983		18,983
2019		23,713		23,713
2018		17,437		17,437
Prior		39,280		39,280
Revolving Loans Amortized Cost Basis		9,089		9,089
Revolving Loan Converted to Term		0		0
Total loans		197,158		197,158
Total loans, net						168,716
2022				0
2021				0
2020				0
2019				0
2018				0
Prior				40
Revolving Loans Amortized Cost Basis Writeoffs				0
Revolving Loan Converted to Term Writeoffs				0
Current-period Gross writeoffs				40
Commercial [Member] | Commercial Real Estate [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans	[1]	165,888		165,888
Total loans, net	[1]					147,063
Commercial [Member] | Commercial Real Estate [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans		31,270		31,270
Total loans, net						21,653
Commercial [Member] | Commercial Real Estate [Member] | Pass [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		58,331		58,331
2021		30,325		30,325
2020		18,803		18,803
2019		23,713		23,713
2018		17,058		17,058
Prior		38,102		38,102
Revolving Loans Amortized Cost Basis		9,089		9,089
Revolving Loan Converted to Term		0		0
Total loans		195,421		195,421
Total loans, net						166,613
Commercial [Member] | Commercial Real Estate [Member] | Pass [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						145,500
Commercial [Member] | Commercial Real Estate [Member] | Pass [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						21,113
Commercial [Member] | Commercial Real Estate [Member] | Special Mention [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		0		0
2021		0		0
2020		65		65
2019		0		0
2018		247		247
Prior		0		0
Revolving Loans Amortized Cost Basis		0		0
Revolving Loan Converted to Term		0		0
Total loans		312		312
Commercial [Member] | Commercial Real Estate [Member] | Substandard [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		0		0
2021		0		0
2020		115		115
2019		0		0
2018		132		132
Prior		1,178		1,178
Revolving Loans Amortized Cost Basis		0		0
Revolving Loan Converted to Term		0		0
Total loans		1,425		1,425
Commercial [Member] | Commercial Real Estate [Member] | Classified [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						2,103
Commercial [Member] | Commercial Real Estate [Member] | Classified [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						1,563
Commercial [Member] | Commercial Real Estate [Member] | Classified [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						540
Commercial [Member] | Other [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		2,302		2,302
2021		3,653		3,653
2020		2,757		2,757
2019		706		706
2018		752		752
Prior		2,472		2,472
Revolving Loans Amortized Cost Basis		7,320		7,320
Revolving Loan Converted to Term		0		0
Total loans		19,962		19,962
Total loans, net						31,484
2022				0
2021				0
2020				0
2019				0
2018				0
Prior				0
Revolving Loans Amortized Cost Basis Writeoffs				0
Revolving Loan Converted to Term Writeoffs				0
Current-period Gross writeoffs				0
Commercial [Member] | Other [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans	[1]	19,089		19,089
Total loans, net	[1]					30,889
Commercial [Member] | Other [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans		873		873
Total loans, net						595
Commercial [Member] | Other [Member] | Pass [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		2,302		2,302
2021		3,313		3,313
2020		2,757		2,757
2019		706		706
2018		752		752
Prior		2,472		2,472
Revolving Loans Amortized Cost Basis		7,182		7,182
Revolving Loan Converted to Term		0		0
Total loans		19,484		19,484
Total loans, net						31,321
Commercial [Member] | Other [Member] | Pass [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						30,726
Commercial [Member] | Other [Member] | Pass [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						595
Commercial [Member] | Other [Member] | Special Mention [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		0		0
2021		124		124
2020		0		0
2019		0		0
2018		0		0
Prior		0		0
Revolving Loans Amortized Cost Basis		40		40
Revolving Loan Converted to Term		0		0
Total loans		164		164
Commercial [Member] | Other [Member] | Substandard [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		0		0
2021		216		216
2020		0		0
2019		0		0
2018		0		0
Prior		0		0
Revolving Loans Amortized Cost Basis		98		98
Revolving Loan Converted to Term		0		0
Total loans		314		314
Commercial [Member] | Other [Member] | Classified [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						163
Commercial [Member] | Other [Member] | Classified [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						163
Commercial [Member] | Other [Member] | Classified [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans, net						0
Real Estate Mortgage - 1 to 4 Family [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans		4,401,706		4,401,706
Total loans, net						4,229,163
Current-period Gross writeoffs		13	73	25	179
Real Estate Mortgage - 1 to 4 Family [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Current-period Gross writeoffs	[1]	13	72	25	178
Real Estate Mortgage - 1 to 4 Family [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Current-period Gross writeoffs		0	1	0	1
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		417,902		417,902
2021		951,063		951,063
2020		800,036		800,036
2019		375,276		375,276
2018		262,857		262,857
Prior		1,266,100		1,266,100
Revolving Loans Amortized Cost Basis		1,479		1,479
Revolving Loan Converted to Term		0		0
Total loans		4,074,713		4,074,713
Total loans, net						3,936,302
2022				0
2021				0
2020				0
2019				0
2018				0
Prior				5
Revolving Loans Amortized Cost Basis Writeoffs				0
Revolving Loan Converted to Term Writeoffs				0
Current-period Gross writeoffs				5
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans	[1]	2,762,616		2,762,616
Total loans, net	[1]					2,723,734
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans		1,312,097		1,312,097
Total loans, net						1,212,568
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | Performing [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		417,902		417,902
2021		950,363		950,363
2020		799,953		799,953
2019		374,430		374,430
2018		262,084		262,084
Prior		1,252,690		1,252,690
Revolving Loans Amortized Cost Basis		1,479		1,479
Revolving Loan Converted to Term		0		0
Total loans		4,058,901		4,058,901
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | Nonperforming [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		0		0
2021		700		700
2020		83		83
2019		846		846
2018		773		773
Prior		13,410		13,410
Revolving Loans Amortized Cost Basis		0		0
Revolving Loan Converted to Term		0		0
Total loans		15,812		15,812
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		5,222		5,222
2021		9,748		9,748
2020		6,535		6,535
2019		7,782		7,782
2018		5,468		5,468
Prior		22,897		22,897
Revolving Loans Amortized Cost Basis		0		0
Revolving Loan Converted to Term		0		0
Total loans		57,652		57,652
Total loans, net						61,885
2022				0
2021				0
2020				0
2019				0
2018				0
Prior				0
Revolving Loans Amortized Cost Basis Writeoffs				0
Revolving Loan Converted to Term Writeoffs				0
Current-period Gross writeoffs				0
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans	[1]	45,115		45,115
Total loans, net	[1]					48,190
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans		12,537		12,537
Total loans, net						13,695
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | Performing [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		5,222		5,222
2021		9,748		9,748
2020		6,535		6,535
2019		7,782		7,782
2018		5,468		5,468
Prior		22,729		22,729
Revolving Loans Amortized Cost Basis		0		0
Revolving Loan Converted to Term		0		0
Total loans		57,484		57,484
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | Nonperforming [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		0		0
2021		0		0
2020		0		0
2019		0		0
2018		0		0
Prior		168		168
Revolving Loans Amortized Cost Basis		0		0
Revolving Loan Converted to Term		0		0
Total loans		168		168
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		698		698
2021		866		866
2020		335		335
2019		56		56
2018		101		101
Prior		21,033		21,033
Revolving Loans Amortized Cost Basis		246,252		246,252
Revolving Loan Converted to Term		0		0
Total loans		269,341		269,341
Total loans, net						230,976
2022				0
2021				0
2020				0
2019				0
2018				0
Prior				20
Revolving Loans Amortized Cost Basis Writeoffs				0
Revolving Loan Converted to Term Writeoffs				0
Current-period Gross writeoffs				20
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans	[1]	186,146		186,146
Total loans, net	[1]					175,134
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans		83,195		83,195
Total loans, net						55,842
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | Performing [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		698		698
2021		859		859
2020		335		335
2019		56		56
2018		101		101
Prior		18,826		18,826
Revolving Loans Amortized Cost Basis		246,047		246,047
Revolving Loan Converted to Term		0		0
Total loans		266,922		266,922
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | Nonperforming [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		0		0
2021		7		7
2020		0		0
2019		0		0
2018		0		0
Prior		2,207		2,207
Revolving Loans Amortized Cost Basis		205		205
Revolving Loan Converted to Term		0		0
Total loans		2,419		2,419
Installment [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		4,068		4,068
2021		2,783		2,783
2020		943		943
2019		985		985
2018		469		469
Prior		293		293
Revolving Loans Amortized Cost Basis		1,124		1,124
Revolving Loan Converted to Term		0		0
Total loans		10,665		10,665
Total loans, net						9,416
2022				0
2021				36
2020				6
2019				6
2018				2
Prior				3
Revolving Loans Amortized Cost Basis Writeoffs				0
Revolving Loan Converted to Term Writeoffs				0
Current-period Gross writeoffs		34	17	53	27
Installment [Member] | New York and Other States [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans	[1]	8,183		8,183
Total loans, net	[1]					7,368
Current-period Gross writeoffs	[1]	34	17	53	25
Installment [Member] | Florida [Member]
Credit Risk Profile, Segregated by Class [Abstract]
Total loans		2,482		2,482
Total loans, net						$ 2,048
Current-period Gross writeoffs		0	$ 0	0	$ 2
Installment [Member] | Performing [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		4,068		4,068
2021		2,758		2,758
2020		943		943
2019		918		918
2018		469		469
Prior		293		293
Revolving Loans Amortized Cost Basis		1,122		1,122
Revolving Loan Converted to Term		0		0
Total loans		10,571		10,571
Installment [Member] | Nonperforming [Member]
Credit Risk Profile, Segregated by Class [Abstract]
2022		0		0
2021		25		25
2020		0		0
2019		67		67
2018		0		0
Prior		0		0
Revolving Loans Amortized Cost Basis		2		2
Revolving Loan Converted to Term		0		0
Total loans		$ 94		$ 94

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