Business Acquisition - Narrative (Details) - USD ($) $ in Thousands			3 Months Ended		9 Months Ended
		Jan. 29, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill			$ 75,717		$ 75,717		$ 0
Initial allowance for PCD assets acquired during the period at acquisition date					30,378
Total net revenue	[1]		246,166	$ 71,044	$ 556,387	$ 242,588
Core Deposit Intangibles
Business Acquisition [Line Items]
Intangible assets, amortized period					10 years
Radius Bancorp, Inc. Merger
Business Acquisition [Line Items]
Goodwill		$ 75,717
Business combination, acquisition related costs		$ 16,000
Total net revenue			$ 19,600		$ 56,400
Radius Bancorp, Inc. Merger | Non-PCD Loans
Business Acquisition [Line Items]
Initial allowance for PCD assets acquired during the period at acquisition date					6,900
Radius Bancorp, Inc. Merger | PCD Loans
Business Acquisition [Line Items]
Initial allowance for PCD assets acquired during the period at acquisition date					$ 12,400

[1] Prior period amounts have been reclassified to conform to the current period presentation. See “Notes to Condensed Consolidated Financial Statements – Note 1. Summary of Significant Accounting Policies” for additional information.