Loans and Allowance for Loan Losses, Risk Category of Loans (Details) - USD ($) $ in Thousands		Sep. 30, 2019	Dec. 31, 2018
Loans and Leases Receivable [Abstract]
Total loans, net		$ 3,985,319	$ 3,874,096
Impaired loans included in classified loans		1,500	1,400
New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	2,991,195	2,948,069
Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		994,124	926,027
Commercial [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		192,443	196,146
Commercial [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	177,678	180,608
Commercial [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		14,765	15,538
Commercial [Member] | Pass [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		187,292	190,802
Commercial [Member] | Pass [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	172,527	175,376
Commercial [Member] | Pass [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		14,765	15,426
Commercial [Member] | Classified [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		5,151	5,344
Commercial [Member] | Classified [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	5,151	5,232
Commercial [Member] | Classified [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		0	112
Commercial [Member] | Commercial Real Estate [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		173,267	171,553
Commercial [Member] | Commercial Real Estate [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	158,766	156,278
Commercial [Member] | Commercial Real Estate [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		14,501	15,275
Commercial [Member] | Commercial Real Estate [Member] | Pass [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		169,109	167,208
Commercial [Member] | Commercial Real Estate [Member] | Pass [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	154,608	152,045
Commercial [Member] | Commercial Real Estate [Member] | Pass [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		14,501	15,163
Commercial [Member] | Commercial Real Estate [Member] | Classified [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		4,158	4,345
Commercial [Member] | Commercial Real Estate [Member] | Classified [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	4,158	4,233
Commercial [Member] | Commercial Real Estate [Member] | Classified [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		0	112
Commercial [Member] | Other [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		19,176	24,593
Commercial [Member] | Other [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	18,912	24,330
Commercial [Member] | Other [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		264	263
Commercial [Member] | Other [Member] | Pass [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		18,183	23,594
Commercial [Member] | Other [Member] | Pass [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	17,919	23,331
Commercial [Member] | Other [Member] | Pass [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		264	263
Commercial [Member] | Other [Member] | Classified [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		993	999
Commercial [Member] | Other [Member] | Classified [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	993	999
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.