Fair Values of Assets and Liabilities - Narrative (Details)	6 Months Ended
	Jun. 30, 2024 USD ($) $ / shares	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 4,329,957,000		$ 3,502,915,000	$ 3,492,481,000
Loans held-for-investment	135,834,000			200,447,000
MSRs	204,610,000	$ 201,044,000	192,456,000	200,692,000	$ 224,470,000	$ 230,225,000
Individually assessed loans - foreclosure probable and collateral-dependent	118,286,000			73,804,000
Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	4,329,957,000		3,502,915,000	3,492,481,000
Remaining contractual principal balance outstanding, mortgage loans held-for-sale	414,100,000		291,700,000	345,700,000
Remaining contractual principal balance outstanding, mortgage loans held-for-investment	136,100,000		156,900,000	196,600,000
Non-performing
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale classified as nonaccrual	2,100,000		649,000	582,000
Mortgage loans held-for-sale classified greater than 90 days past due and still accruing	$ 39,400,000		26,600,000	29,600,000
Weighted Average | Loans held-for-investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Life of loans	5 years 10 months 24 days
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	$ 411,851,000		292,722,000	338,728,000
Loans held-for-investment	135,834,000		155,261,000	193,953,000
MSRs	204,610,000		192,456,000	200,692,000
Derivative assets	243,860,000		275,726,000	294,748,000
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	118,286,000
Other real estate owned	19,731,000
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually assessed loans - foreclosure probable and collateral-dependent	118,300,000
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	40,545,000		26,835,000	29,406,000
Loans held-for-investment	45,721,000		60,670,000	61,123,000
MSRs	204,610,000		192,456,000	200,692,000
Derivative assets	$ 4,795,000		4,510,000	3,487,000
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	0.1098
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	0.0683
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	0.0683
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	0.1098
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	0.01
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	0.01
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	0.36
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	0.36
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	0.0036
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	0.0110
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	0.13
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	0.17
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	0.0786
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	0.0786
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	0.0786
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	361
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	0.8117
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	0.04
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	$ 118,286,000
Other real estate owned	19,731,000
Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	146,608,000		140,958,000	167,411,000
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	146,608,000		140,958,000	167,411,000
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	$ 95,792,000		$ 86,237,000	$ 114,155,000