Acquisitions - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Nov. 20, 2021	Sep. 30, 2023	Dec. 31, 2022	Nov. 19, 2021
Assets Acquired
Goodwill		$ 1,320,799	$ 1,319,598
Spirit of Texas Bancshares, Inc.
Assets Acquired
Cash and due from banks	$ 277,790			$ 277,790
Investment securities	348,687			362,088
Loans acquired	2,294,160			2,314,085
Allowance for credit losses on loans	(9,623)			(17,005)
Premises and equipment	65,061			84,135
Bank owned life insurance	36,890			36,890
Goodwill	0			77,681
Other assets	54,992			58,403
Total assets acquired	3,106,588			3,200,312
Liabilities Assumed
Noninterest bearing transaction accounts	824,694			825,228
Interest bearing transaction accounts and savings deposits	1,383,663			1,383,663
Time deposits	510,290			509,209
Total deposits	2,718,647			2,718,100
Other borrowings	38,050			37,547
Subordinated debentures	37,370			36,491
Accrued interest and other liabilities	20,356			23,667
Total liabilities assumed	2,814,423			2,815,805
Equity	0			384,507
Total liabilities and equity assumed	2,814,423			3,200,312
Net assets acquired	292,165
Purchase price	466,311
Goodwill	174,146
Spirit of Texas Bancshares, Inc. | Fair Value Adjustments
Assets Acquired
Cash and due from banks	0
Investment securities	(13,401)
Loans acquired	(19,925)
Allowance for credit losses on loans	7,382
Premises and equipment	(19,074)
Bank owned life insurance	0
Goodwill	(77,681)
Other assets	(3,411)
Total assets acquired	(93,724)
Liabilities Assumed
Noninterest bearing transaction accounts	(534)
Interest bearing transaction accounts and savings deposits	0
Time deposits	1,081
Total deposits	547
Other borrowings	503
Subordinated debentures	879
Accrued interest and other liabilities	(3,311)
Total liabilities assumed	(1,382)
Equity	(384,507)
Total liabilities and equity assumed	(385,889)
Core Deposit Premium | Spirit of Texas Bancshares, Inc.
Assets Acquired
Core deposit and other intangible assets	38,631			$ 6,245
Core Deposit Premium | Spirit of Texas Bancshares, Inc. | Fair Value Adjustments
Assets Acquired
Core deposit and other intangible assets	$ 32,386