Loans and the Allowance for Loan Losses (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) Loans	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Financing Receivable, Impaired [Line Items]
Gross loans	$ 6,247,681	$ 5,118,294
Non Accrual Contractual Due	90 days
Loans Pledged as Collateral	$ 2,700,000	2,500,000
Charge offs	900	5,076	$ 18,011
Loans performing under the restructured terms	23,700	21,400
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans	25,700	30,600
Troubled debt restructurings	49,400	52,000
Specific allowance	$ 0	1,300
Number of deferred loans | Loans	113
Deferred loan	$ 207,081
Allowance for loan and lease losses, collectively evaluated for impairment	59,072	$ 35,784
Special Mention [Member]
Financing Receivable, Impaired [Line Items]
Deferred loan	$ 40,300
Minimum [Member]
Financing Receivable, Impaired [Line Items]
Deferred period of loan	90 days
Maximum [Member]
Financing Receivable, Impaired [Line Items]
Deferred period of loan	120 days
Taxi medallion loans [Member]
Financing Receivable, Impaired [Line Items]
Charge offs			$ 17,000
Number of loans		one taxi medallion loan	27 taxi medallion loans
Value of taxi medallion loans Included in the commercial loan segment of the troubled debt restructurings		$ 300	$ 112
PPP loans [Member]
Financing Receivable, Impaired [Line Items]
Gross loans	$ 397,500
Allowance for loan and lease losses, collectively evaluated for impairment	$ 397,500