Loans and Allowance for Loan Losses, Risk Category of Loans (Details) - USD ($) $ in Thousands		Jun. 30, 2018	Dec. 31, 2017
Loans and Leases Receivable [Abstract]
Total loans, net		$ 3,741,155	$ 3,636,407
Non-accrual loans included in classified loans		1,000	2,200
New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	2,857,191	2,795,993
Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		883,964	840,414
Commercial [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		190,904	186,207
Commercial [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	180,022	172,974
Commercial [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		10,882	13,233
Commercial [Member] | Pass [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		183,178	175,857
Commercial [Member] | Pass [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	172,412	162,742
Commercial [Member] | Pass [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		10,766	13,115
Commercial [Member] | Classified [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		7,726	10,350
Commercial [Member] | Classified [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	7,610	10,232
Commercial [Member] | Classified [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		116	118
Commercial [Member] | Commercial Real Estate [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		165,322	161,892
Commercial [Member] | Commercial Real Estate [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	154,750	149,368
Commercial [Member] | Commercial Real Estate [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		10,572	12,524
Commercial [Member] | Commercial Real Estate [Member] | Pass [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		159,108	153,212
Commercial [Member] | Commercial Real Estate [Member] | Pass [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	148,652	140,806
Commercial [Member] | Commercial Real Estate [Member] | Pass [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		10,456	12,406
Commercial [Member] | Commercial Real Estate [Member] | Classified [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		6,214	8,680
Commercial [Member] | Commercial Real Estate [Member] | Classified [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	6,098	8,562
Commercial [Member] | Commercial Real Estate [Member] | Classified [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		116	118
Commercial [Member] | Other [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		25,582	24,315
Commercial [Member] | Other [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	25,272	23,606
Commercial [Member] | Other [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		310	709
Commercial [Member] | Other [Member] | Pass [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		24,070	22,645
Commercial [Member] | Other [Member] | Pass [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	23,760	21,936
Commercial [Member] | Other [Member] | Pass [Member] | Florida [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		310	709
Commercial [Member] | Other [Member] | Classified [Member]
Loans and Leases Receivable [Abstract]
Total loans, net		1,512	1,670
Commercial [Member] | Other [Member] | Classified [Member] | New York and Other States [Member]
Loans and Leases Receivable [Abstract]
Total loans, net	[1]	1,512	1,670
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.