Business, Basis of Financial Statement Presentation and Principles of Consolidation (Details) $ in Thousands	Jun. 05, 2020	Mar. 27, 2020 USD ($)	Sep. 30, 2020 USD ($) Office Loan
Business Basis Of Financial Statement Presentation And Principles Of Consolidation [Line Items]
Number of offices | Office			187
Financing receivable, loans outstanding | Loan			9,691
Financing receivable, loan amount			$ 944,270
Financing receivable, deferred fees and costs			$ 25,700
Small Business Administration (SBA), CARES Act, Paycheck Protection Program [Member]
Business Basis Of Financial Statement Presentation And Principles Of Consolidation [Line Items]
Provision for CARES Act		$ 349,000,000
Financing Receivable, interest rate		1.00%
Financing Receivable, loan term		2 years
Small Business Administration (SBA), CARES Act, Paycheck Protection Program [Member] | Minimum [Member]
Business Basis Of Financial Statement Presentation And Principles Of Consolidation [Line Items]
Financing Receivable, loan term	5 years
Financing Receivable, processing fee percentage	1.00%
Small Business Administration (SBA), CARES Act, Paycheck Protection Program [Member] | Maximum [Member]
Business Basis Of Financial Statement Presentation And Principles Of Consolidation [Line Items]
Financing receivable, existing loans maturity term	5 years
Financing receivable, guaranteed percentage	100.00%
Financing Receivable, processing fee percentage	5.00%