Fair Value of Financial Instruments - Summary of Fair Value Hierarchy and Fair Value of Assets That Were Still Held and Had Fair Value Adjustments Measured On a Nonrecurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financing Receivable Impaired [Line Items]
Impaired loans	$ 1,217,597	$ 1,109,217
Quoted Prices in Active Markets (Level 1)
Financing Receivable Impaired [Line Items]
Impaired loans	0	0
Significant Other Observable Inputs (Level 2)
Financing Receivable Impaired [Line Items]
Impaired loans	0	0
Significant Unobservable Inputs (Level 3)
Financing Receivable Impaired [Line Items]
Impaired loans	1,217,597	1,109,217
Fair Value, Measurements, Nonrecurring
Financing Receivable Impaired [Line Items]
Impaired loans	443	87
Fair Value, Measurements, Nonrecurring | Quoted Prices in Active Markets (Level 1)
Financing Receivable Impaired [Line Items]
Impaired loans	0	0
Fair Value, Measurements, Nonrecurring | Significant Other Observable Inputs (Level 2)
Financing Receivable Impaired [Line Items]
Impaired loans	0	0
Fair Value, Measurements, Nonrecurring | Significant Unobservable Inputs (Level 3)
Financing Receivable Impaired [Line Items]
Impaired loans	$ 443	$ 87