Credit Losses textual (Details) - USD ($)		3 Months Ended								6 Months Ended	12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Credit Loss [Line Items]
Interest Receivable		$ 36,000,000.0									$ 36,000,000.0
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	[1]										(1,137,000)
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	[2]										1,157,000
Loans and Leases Receivable, Allowance		(113,392,000)				$ (67,740,000)					(113,392,000)	$ (67,740,000)	$ (64,293,000)	$ (60,643,000)
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)											$ (45,600,000)
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease) by percentage											67.30%
Provision for credit losses		0	$ 7,500,000	$ 20,000,000	$ 25,000,000	4,000,000	$ 0	$ 1,000,000	$ 1,000,000	$ 4,775,000	$ 52,500,000	6,000,000	$ 4,775,000
Off-Balance Sheet, Credit Loss, Liability		1,200,000									$ 1,200,000
Days To Be Termed As Non Accrual Loans											90 days
Loans with active Deferrals		173,600,000									$ 173,600,000
Tdrs Recorded Investment On Nonaccrual Status		22,209,000				$ 24,766,000					22,209,000	$ 24,766,000
Financing Receivable, Troubled Debt Restructuring, Subsequent Default											0
US Government Insured Loan Program [Member]
Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 791,900,000									$ 791,900,000

[1] Represents adjustment needed to reflect the cumulative day one impact pursuant to the Company's adoption of Accounting Standards Update 2016-13. The adjustment represents a $1.1 million decrease to the allowance attributable to the change in accounting methodology for estimating the allowance for credit losses resulting from the Company's adoption of the standard.

[2] Represents adjustment needed to reflect the day one reclassification of the Company's PCI loan balances to PCD and the associated gross-up, pursuant to the Company's adoption of Accounting Standards Update 2016-13. The adjustment represents a $1.2 million increase to the allowance resulting from the day one reclassification.