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
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