Fair Values of Assets and Liabilities - Narrative (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 3,502,915,000	$ 3,243,017,000
Loans held-for-investment	155,261,000	179,932,000
MSRs	192,456,000	230,225,000	$ 147,571,000	$ 92,081,000
Individually assessed loans - foreclosure probable and collateral-dependent	91,153,000	90,197,000
Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	3,502,915,000	3,243,017,000
Remaining contractual principal balance outstanding, mortgage loans held-for-sale	291,700,000	308,900,000
Remaining contractual principal balance outstanding, mortgage loans held-for-investment	156,900,000	184,000,000
Non-performing
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale classified as nonaccrual	649,000	5,800,000
Mortgage loans held-for-sale classified greater than 90 days past due and still accruing	$ 26,600,000	44,000,000
Weighted Average | Loans held-for-investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Life of loans	6 years
Appraisal adjustment - cost of sale | Other real estate owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned, measurement input	0.10
Measured at fair value on a recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale	$ 292,722,000	299,935,000
Loans held-for-investment	155,261,000	179,932,000
MSRs	192,456,000	230,225,000
Derivative assets	275,726,000	296,848,000
Measured at fair value on a non-recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually assessed loans - foreclosure probable and collateral-dependent	91,153,000
Other real estate owned	13,309,000
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually assessed loans - foreclosure probable and collateral-dependent	91,200,000
Level 3 | Portion at Other than Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually assessed loans - foreclosure probable and collateral-dependent	0
Level 3 | Measured at fair value on a recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale	26,835,000	48,655,000
Loans held-for-investment	60,670,000	84,165,000
MSRs	192,456,000	230,225,000
Derivative assets	$ 4,510,000	1,711,000
Level 3 | Measured at fair value on a recurring basis: | Discount rate | Weighted Average | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	0.1100
Level 3 | Measured at fair value on a recurring basis: | Discount rate | Weighted Average | Mortgage loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.0611
Level 3 | Measured at fair value on a recurring basis: | Discount rate | Weighted Average | Loans held-for-investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.0618
Level 3 | Measured at fair value on a recurring basis: | Discount rate | Weighted Average | Mortgage Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.1100
Level 3 | Measured at fair value on a recurring basis: | Discount rate | Minimum | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	0.06
Level 3 | Measured at fair value on a recurring basis: | Discount rate | Minimum | Mortgage Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.06
Level 3 | Measured at fair value on a recurring basis: | Discount rate | Maximum | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	0.25
Level 3 | Measured at fair value on a recurring basis: | Discount rate | Maximum | Mortgage Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.25
Level 3 | Measured at fair value on a recurring basis: | Credit discount | Weighted Average | Mortgage loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.0040
Level 3 | Measured at fair value on a recurring basis: | Credit discount | Weighted Average | Loans held-for-investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.0096
Level 3 | Measured at fair value on a recurring basis: | Credit discount | Minimum | Mortgage loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0
Level 3 | Measured at fair value on a recurring basis: | Credit discount | Minimum | Loans held-for-investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0
Level 3 | Measured at fair value on a recurring basis: | Credit discount | Maximum | Mortgage loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.11
Level 3 | Measured at fair value on a recurring basis: | Credit discount | Maximum | Loans held-for-investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.29
Level 3 | Measured at fair value on a recurring basis: | Constant prepayment rate (CPR) | Weighted Average | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	0.0791
Level 3 | Measured at fair value on a recurring basis: | Constant prepayment rate (CPR) | Weighted Average | Loans held-for-investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.0791
Level 3 | Measured at fair value on a recurring basis: | Constant prepayment rate (CPR) | Weighted Average | Mortgage Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.0791
Level 3 | Measured at fair value on a recurring basis: | Constant prepayment rate (CPR) | Minimum | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	0
Level 3 | Measured at fair value on a recurring basis: | Constant prepayment rate (CPR) | Minimum | Mortgage Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0
Level 3 | Measured at fair value on a recurring basis: | Constant prepayment rate (CPR) | Maximum | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	0.90
Level 3 | Measured at fair value on a recurring basis: | Constant prepayment rate (CPR) | Maximum | Mortgage Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.90
Level 3 | Measured at fair value on a recurring basis: | Cost of servicing | Weighted Average | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	77
Level 3 | Measured at fair value on a recurring basis: | Cost of servicing | Minimum | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input | $ / shares	70
Level 3 | Measured at fair value on a recurring basis: | Cost of servicing | Maximum | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input | $ / shares	200
Level 3 | Measured at fair value on a recurring basis: | Cost of servicing - delinquent | Weighted Average | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	393
Level 3 | Measured at fair value on a recurring basis: | Cost of servicing - delinquent | Minimum | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input | $ / shares	200
Level 3 | Measured at fair value on a recurring basis: | Cost of servicing - delinquent | Maximum | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input | $ / shares	1,000
Level 3 | Measured at fair value on a recurring basis: | Pull-through rate | Weighted Average | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, measurement input	0.7396
Level 3 | Measured at fair value on a recurring basis: | Pull-through rate | Minimum | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, measurement input	0.06
Level 3 | Measured at fair value on a recurring basis: | Pull-through rate | Maximum | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, measurement input	1
Level 3 | Measured at fair value on a non-recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually assessed loans - foreclosure probable and collateral-dependent	$ 91,153,000
Other real estate owned	13,309,000
Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	140,958,000	168,655,000
Municipal securities | Measured at fair value on a recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	140,958,000	168,655,000
Municipal securities | Level 3 | Measured at fair value on a recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 86,237,000	$ 117,537,000