General - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2021		Jun. 30, 2021	Jan. 01, 2021	Dec. 31, 2020		Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	$ (832,728)				$ (788,578)
Allowance for credit losses - Loans	199,972	[1]	$ 199,775		130,648	[1]	$ 126,726	$ 121,119	$ 80,284
Allowance for credit losses on unfunded loan commitments	20,500		$ 20,500		0
Allowance for credit losses	245				0
Loans	9,041,576				9,243,174
PPP loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	198,100				667,100
State and municipal
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses	245				0
Cumulative effect of ASC 326 adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings				$ 68,040
Percent of increase in allowance				57.00%
Allowance for credit losses - Loans				$ 74,055	74,055
Allowance for credit losses on unfunded loan commitments	$ 20,500			20,500
Loans				4,776
Cumulative effect of ASC 326 adoption | State and municipal
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses				$ 245	$ 245

[1] Beginning January 1, 2021, the amount is based on the current expected credit loss methodology. Prior to January 1, 2021, the amount is based on the incurred loss methodology. See additional details in NOTE 1. GENERAL of these Notes to Consolidated Condensed Financial Statement.