Loans and Allowance for Loan Losses, Risk Category of Loans (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Loans and Leases Receivable [Abstract]
Total loans, net		$ 4,214,555	$ 4,062,196
Impaired loans included in classified loans		849	816
New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	3,064,654	3,022,936
Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		1,149,901	1,039,260
Commercial [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		231,663	199,499
Commercial [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[2]	212,880	181,512
Commercial [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		18,783	17,987
Commercial [Member] | Pass [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		227,479	193,651
Commercial [Member] | Pass [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[2]	209,270	175,664
Commercial [Member] | Pass [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		18,209	17,987
Commercial [Member] | Classified [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		4,184	5,848
Commercial [Member] | Classified [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[2]	3,610	5,848
Commercial [Member] | Classified [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		574	0
Commercial [Member] | Commercial Real Estate [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		171,573	179,938
Commercial [Member] | Commercial Real Estate [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1],[2]	152,994	162,186
Commercial [Member] | Commercial Real Estate [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		18,579	17,752
Commercial [Member] | Commercial Real Estate [Member] | Pass [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		167,871	175,032
Commercial [Member] | Commercial Real Estate [Member] | Pass [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[2]	149,866	157,280
Commercial [Member] | Commercial Real Estate [Member] | Pass [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		18,005	17,752
Commercial [Member] | Commercial Real Estate [Member] | Classified [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		3,702	4,906
Commercial [Member] | Commercial Real Estate [Member] | Classified [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[2]	3,128	4,906
Commercial [Member] | Commercial Real Estate [Member] | Classified [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		574	0
Commercial [Member] | Other [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		60,090	19,561
Commercial [Member] | Other [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1],[2]	59,886	19,326
Commercial [Member] | Other [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		204	235
Commercial [Member] | Other [Member] | Pass [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		59,608	18,619
Commercial [Member] | Other [Member] | Pass [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[2]	59,404	18,384
Commercial [Member] | Other [Member] | Pass [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		204	235
Commercial [Member] | Other [Member] | Classified [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		482	942
Commercial [Member] | Other [Member] | Classified [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[2]	482	942
Commercial [Member] | Other [Member] | Classified [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		$ 0	$ 0

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

[2] Includes New York, New Jersey and Massachusetts.