Fair Values of Assets and Liabilities - Narrative (Details)	3 Months Ended
	Mar. 31, 2025 USD ($) $ / shares	Dec. 31, 2024 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	$ 4,220,305,000	$ 4,141,482,000	$ 4,387,598,000
Loans held-for-investment	126,521,000		144,365,000
MSRs	196,307,000	203,788,000	201,044,000	$ 192,456,000
Individually measured	121,269,000		89,368,000
Non-performing
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale classified as nonaccrual	2,800,000	4,000,000.0	1,300,000
Mortgage loans held-for-sale classified greater than 90 days past due and still accruing	56,200,000	59,300,000	33,200,000
Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	4,220,305,000	4,141,482,000	4,387,598,000
Remaining contractual principal balance outstanding, mortgage loans held-for-sale	319,600,000	335,900,000	342,700,000
Remaining contractual principal balance outstanding, mortgage loans held-for-investment	$ 126,500,000	157,800,000	145,900,000
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
Weighted Average | Loans held-for- investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Life of loans	6 years 6 months
Municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	$ 188,149,000	184,593,000	140,590,000
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	316,804,000	331,261,000	339,884,000
Loans held-for-investment	126,521,000	158,795,000	144,371,000
MSRs	196,307,000	203,788,000	201,044,000
Derivative asset	204,257,000	200,027,000	259,264,000
Measured at fair value on a recurring basis: | Municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	188,149,000	184,593,000	140,590,000
Measured at fair value on a non-recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually measured	121,269,000
Other real estate owned	22,625,000
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually measured	121,300,000
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	56,324,000	60,399,000	33,726,000
Loans held-for-investment	34,002,000	34,896,000	49,317,000
MSRs	196,307,000	203,788,000	201,044,000
Derivative asset	$ 5,493,000	1,950,000	6,212,000
Level 3 | Measured at fair value on a recurring basis: | Weighted Average | Measurement Input, Discount Rate | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	0.1094
Level 3 | Measured at fair value on a recurring basis: | Weighted Average | Constant prepayment rate (CPR) - current loans | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	0.0892
Level 3 | Measured at fair value on a recurring basis: | Weighted Average | Cost of servicing | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	76
Level 3 | Measured at fair value on a recurring basis: | Weighted Average | Cost of servicing - delinquent | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	402
Level 3 | Measured at fair value on a recurring basis: | Weighted Average | Pull-through rate | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, measurement input	0.838
Level 3 | Measured at fair value on a recurring basis: | Weighted Average | Mortgage loans held-for-sale | Measurement Input, Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.0543
Level 3 | Measured at fair value on a recurring basis: | Weighted Average | Mortgage loans held-for-sale | Credit discount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.0071
Level 3 | Measured at fair value on a recurring basis: | Weighted Average | Loans held-for- investment | Measurement Input, Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.0550
Level 3 | Measured at fair value on a recurring basis: | Weighted Average | Loans held-for- investment | Credit discount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.0112
Level 3 | Measured at fair value on a recurring basis: | Weighted Average | Loans held-for- investment | Constant prepayment rate (CPR) - current loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.0892
Level 3 | Measured at fair value on a recurring basis: | Weighted Average | Mortgage servicing rights | Measurement Input, Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.1094
Level 3 | Measured at fair value on a recurring basis: | Weighted Average | Mortgage servicing rights | Constant prepayment rate (CPR) - current loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.0892
Level 3 | Measured at fair value on a recurring basis: | Minimum | Measurement Input, Discount Rate | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	0.07
Level 3 | Measured at fair value on a recurring basis: | Minimum | Constant prepayment rate (CPR) - current loans | 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: | Minimum | Cost of servicing | 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: | Minimum | Cost of servicing - delinquent | 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: | Minimum | Pull-through rate | 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: | Minimum | Mortgage loans held-for-sale | Credit discount
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: | Minimum | Loans held-for- investment | Credit discount
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: | Minimum | Mortgage servicing rights | Measurement Input, Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.07
Level 3 | Measured at fair value on a recurring basis: | Minimum | Mortgage servicing rights | Constant prepayment rate (CPR) - current loans
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: | Maximum | Measurement Input, Discount Rate | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	0.18
Level 3 | Measured at fair value on a recurring basis: | Maximum | Constant prepayment rate (CPR) - current loans | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs, measurement input	0.91
Level 3 | Measured at fair value on a recurring basis: | Maximum | Cost of servicing | 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: | Maximum | Cost of servicing - delinquent | 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: | Maximum | Pull-through rate | 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 recurring basis: | Maximum | Mortgage loans held-for-sale | Credit discount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.18
Level 3 | Measured at fair value on a recurring basis: | Maximum | Loans held-for- investment | Credit discount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.10
Level 3 | Measured at fair value on a recurring basis: | Maximum | Mortgage servicing rights | Measurement Input, Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.18
Level 3 | Measured at fair value on a recurring basis: | Maximum | Mortgage servicing rights | Constant prepayment rate (CPR) - current loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.91
Level 3 | Measured at fair value on a recurring basis: | Municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	$ 121,844,000	$ 121,607,000	$ 88,219,000
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 measured	121,269,000
Other real estate owned	$ 22,625,000