Fair Value of Assets and Liabilities - Summary of the Significant Unobservable Inputs (Details) - Significant Other Unobservable Inputs (Level 3) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Discounted Cash Flow | Interest Rate Swap Agreements
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	$ 29,887	$ 72,933
Discounted Cash Flow | Weighted Average Constant Prepayment Rate (as a percent)
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Mortgage Servicing Rights, Fair Value Inputs	0.0667	0.0581
Discounted Cash Flow | Weighted Average Credit Factor (as a percent) | Interest Rate Swap Agreements
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Fair Value Inputs	0.0014	0.0029
Discounted Cash Flow | Mortgage Servicing Rights
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Mortgage Servicing Rights, at Fair Value	$ 22,099	$ 19,652
Discounted Cash Flow | Mortgage Servicing Rights | Weighted Average Constant Prepayment Rate (as a percent)
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Mortgage Servicing Rights, Fair Value Inputs	0.1150	0.1442
Pricing Model | Interest Rate Lock Commitments
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	$ 1,222	$ 4,947
Pricing Model | Weighted Average Closing Ratio (as a percent) | Interest Rate Lock Commitments
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Fair Value Inputs	0.9284	0.9076
Minimum | Discounted Cash Flow | Weighted Average Constant Prepayment Rate (as a percent)
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Mortgage Servicing Rights, Fair Value Inputs	0.0565	0.0569
Minimum | Discounted Cash Flow | Weighted Average Credit Factor (as a percent) | Interest Rate Swap Agreements
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Fair Value Inputs	0.0000	0.0000
Minimum | Discounted Cash Flow | Mortgage Servicing Rights
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities, Discount Rate	8.13%	8.71%
Minimum | Pricing Model | Weighted Average Closing Ratio (as a percent) | Interest Rate Lock Commitments
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Fair Value Inputs	0.8410	0.8410
Maximum | Discounted Cash Flow | Weighted Average Constant Prepayment Rate (as a percent)
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Mortgage Servicing Rights, Fair Value Inputs	0.0674	0.0628
Maximum | Discounted Cash Flow | Weighted Average Credit Factor (as a percent) | Interest Rate Swap Agreements
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Fair Value Inputs	0.0049	0.0049
Maximum | Discounted Cash Flow | Mortgage Servicing Rights
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities, Discount Rate	14.43%	15.89%
Maximum | Pricing Model | Weighted Average Closing Ratio (as a percent) | Interest Rate Lock Commitments
Level3 Assets And Liabilities Fair Value And Fair Value Unobservable Inputs [Line Items]
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Fair Value Inputs	1.0000	0.9900