Mortgage Banking Activities, Mortgage Servicing Rights (Details)	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Summary of Mortgage Servicing Rights [Abstract]
Number of residential mortgage loans serviced for others	102,008	106,201	126,828
Outstanding principal balance of residential mortgage loans serviced for others	$ 16,442,446,000	$ 16,228,449,000	$ 20,727,106,000
Weighted average interest rate (in hundredths)	3.58%	3.84%	3.98%
Remaining contractual term (in months)	281 months	280 months	289 months
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	$ 101,172,000	$ 201,886,000	$ 259,254,000
Additions	31,132,000	31,209,000	35,128,000
Acquisitions	28,018,000
Disposals		(10,801,000)
Change in fair value due to loan runoff	(38,761,000)	(41,598,000)	(38,979,000)
Change in fair value due to market changes	41,637,000	(79,524,000)	(53,517,000)
Ending balance	$ 163,198,000	$ 101,172,000	$ 201,886,000
Servicing Assets at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Discount rate - risk-free rate plus a market premium (in hundredths)	8.39%	9.14%
Prepayment rate - based upon loan interest rate, original term and loan type	12.11%	19.73%
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
Primary secondary mortgage rate spread (in basis points)	105	105
Escrow earnings rate - indexed to rates paid on deposit accounts with comparable average life	1.32%	0.43%
Delinquency rate	2.05%	3.54%