Mortgage Banking Activities, Mortgage Servicing Rights (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Summary of Mortgage Servicing Rights [Abstract]
Number of residential mortgage loans serviced for others	99,409		102,008
Outstanding principal balance of residential mortgage loans serviced for others	$ 16,024,663,000		$ 16,442,446,000
Weighted average interest rate	3.57%		3.58%
Remaining term (in months)	281 months		281 months
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	$ 163,198,000	$ 101,172,000	$ 101,172,000
Additions	5,215,000	9,830,000
Changes due to principal payments	(7,960,000)	(11,961,000)
Change in fair value due to market assumption changes	49,110,000	33,874,000
Ending balance	$ 209,563,000	$ 132,915,000	$ 163,198,000
Servicing Assets at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Discount rate - risk-free rate plus a market premium (in hundredths)	8.53%		8.39%
Prepayment rate - based upon loan interest rate, original term and loan type	8.48%		12.11%
Loan servicing costs - annually per loan based upon loan type, performing, minimum (in dollars per loan)	$ 69		$ 69
Loan servicing costs - annually per loan based upon loan type, performing, maximum (in dollars per loan)	94		94
Loan servicing costs - annually per loan based upon loan type, delinquent, minimum (in dollars per loan)	150		150
Loan servicing costs - annually per loan based upon loan type, delinquent, maximum (in dollars per loan)	500		500
Loan servicing costs - annually per loan based upon loan type, foreclosure, minimum (in dollars per loan)	1,000		1,000
Loan servicing costs - annually per loan based upon loan type, foreclosure, maximum (in dollars per loan)	$ 4,000		$ 4,000
Escrow earnings rate - indexed to rates paid on deposit accounts with comparable average life (in hundredths)	2.47%		1.32%
Primary secondary mortgage rate spread	105		105
Delinquency rate	2.28%		2.05%