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Fair Values of Assets and Liabilities - Schedule of Balances of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands | Sep. 30, 2023 | Jun. 30, 2023 | Dec. 31, 2022 | Sep. 30, 2022 | Jun. 30, 2022 | Dec. 31, 2021
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Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | $ 3,611,835 |  | $ 3,243,017 | $ 2,923,653 |  |
Equity securities with readily determinable fair value | 134,310 |  | 110,365 | 114,012 |  |
Loans held-for-investment | 171,178 |  |  | 156,893 |  |
MSRs | 210,524 | $ 200,692 | 230,225 | 229,671 | $ 212,664 | $ 147,571
U.S. Treasury |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 4,931 |  | 14,948 | 0 |  |
U.S. government agencies |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 72,430 |  | 74,222 | 44,013 |  |
Municipal securities |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 168,523 |  | 168,655 | 174,001 |  |
Measured at fair value on a recurring basis: |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Trading account securities | 1,663 |  | 1,127 | 179 |  |
Equity securities with readily determinable fair value | 134,310 |  | 110,365 | 114,012 |  |
Mortgage loans held-for-sale | 304,808 |  | 299,935 | 376,160 |  |
Loans held-for-investment | 171,178 |  | 179,932 | 156,893 |  |
MSRs | 210,524 |  | 230,225 | 229,671 |  |
Nonqualified deferred compensation assets | 14,449 |  | 13,899 | 13,387 |  |
Derivative assets | 323,705 |  | 296,848 | 313,480 |  |
Total | 4,772,472 |  | 4,375,348 | 4,127,435 |  |
Derivative liabilities | 458,706 |  | 338,078 | 357,170 |  |
Measured at fair value on a recurring basis: | Level 1 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Trading account securities | 0 |  | 0 | 0 |  |
Equity securities with readily determinable fair value | 126,244 |  | 102,299 | 105,946 |  |
Mortgage loans held-for-sale | 0 |  | 0 | 0 |  |
Loans held-for-investment | 0 |  | 0 | 0 |  |
MSRs | 0 |  | 0 | 0 |  |
Nonqualified deferred compensation assets | 0 |  | 0 | 0 |  |
Derivative assets | 0 |  | 0 | 0 |  |
Total | 131,175 |  | 117,247 | 105,946 |  |
Derivative liabilities | 0 |  | 0 | 0 |  |
Measured at fair value on a recurring basis: | Level 2 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Trading account securities | 1,663 |  | 1,127 | 179 |  |
Equity securities with readily determinable fair value | 8,066 |  | 8,066 | 8,066 |  |
Mortgage loans held-for-sale | 279,621 |  | 251,280 | 327,740 |  |
Loans held-for-investment | 113,217 |  | 95,767 | 58,326 |  |
MSRs | 0 |  | 0 | 0 |  |
Nonqualified deferred compensation assets | 14,449 |  | 13,899 | 13,387 |  |
Derivative assets | 321,189 |  | 295,137 | 313,339 |  |
Total | 4,231,890 |  | 3,775,808 | 3,522,258 |  |
Derivative liabilities | 458,706 |  | 338,078 | 357,170 |  |
Measured at fair value on a recurring basis: | Level 3 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Trading account securities | 0 |  | 0 | 0 |  |
Equity securities with readily determinable fair value | 0 |  | 0 | 0 |  |
Mortgage loans held-for-sale | 25,187 |  | 48,655 | 48,420 |  |
Loans held-for-investment | 57,961 |  | 84,165 | 98,567 |  |
MSRs | 210,524 |  | 230,225 | 229,671 |  |
Nonqualified deferred compensation assets | 0 |  | 0 | 0 |  |
Derivative assets | 2,516 |  | 1,711 | 141 |  |
Total | 409,407 |  | 482,293 | 499,231 |  |
Derivative liabilities | 0 |  | 0 | 0 |  |
Measured at fair value on a recurring basis: | U.S. Treasury |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 4,931 |  | 14,948 | 0 |  |
Measured at fair value on a recurring basis: | U.S. Treasury | Level 1 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 4,931 |  | 14,948 | 0 |  |
Measured at fair value on a recurring basis: | U.S. Treasury | Level 2 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 0 |  | 0 | 0 |  |
Measured at fair value on a recurring basis: | U.S. Treasury | Level 3 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 0 |  | 0 | 0 |  |
Measured at fair value on a recurring basis: | U.S. government agencies |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 72,430 |  | 74,222 | 44,013 |  |
Measured at fair value on a recurring basis: | U.S. government agencies | Level 1 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 0 |  | 0 | 0 |  |
Measured at fair value on a recurring basis: | U.S. government agencies | Level 2 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 72,430 |  | 74,222 | 44,013 |  |
Measured at fair value on a recurring basis: | U.S. government agencies | Level 3 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 0 |  | 0 | 0 |  |
Mortgage loans held-for-sale | 25,187 |  |  |  |  |
Measured at fair value on a recurring basis: | Municipal securities |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 168,523 |  | 168,655 | 174,001 |  |
Measured at fair value on a recurring basis: | Municipal securities | Level 1 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 0 |  | 0 | 0 |  |
Measured at fair value on a recurring basis: | Municipal securities | Level 2 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 55,304 |  | 51,118 | 51,569 |  |
Measured at fair value on a recurring basis: | Municipal securities | Level 3 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 113,219 |  | 117,537 | 122,432 |  |
Measured at fair value on a recurring basis: | Corporate notes |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 76,606 |  | 85,705 | 87,033 |  |
Measured at fair value on a recurring basis: | Corporate notes | Level 1 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 0 |  | 0 | 0 |  |
Measured at fair value on a recurring basis: | Corporate notes | Level 2 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 76,606 |  | 85,705 | 87,033 |  |
Measured at fair value on a recurring basis: | Corporate notes | Level 3 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 0 |  | 0 | 0 |  |
Measured at fair value on a recurring basis: | Mortgage-backed |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 3,289,345 |  | 2,899,487 | 2,618,606 |  |
Measured at fair value on a recurring basis: | Mortgage-backed | Level 1 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 0 |  | 0 | 0 |  |
Measured at fair value on a recurring basis: | Mortgage-backed | Level 2 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | 3,289,345 |  | 2,899,487 | 2,618,606 |  |
Measured at fair value on a recurring basis: | Mortgage-backed | Level 3 |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Available-for-sale securities | $ 0 |  | $ 0 | $ 0 |  |

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