Acquisitions - Narrative (Details) - Spirit of Texas Bancshares, Inc.			9 Months Ended	12 Months Ended
	Apr. 08, 2022 USD ($) shares	Nov. 20, 2021 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2023 USD ($)	Nov. 19, 2021 USD ($) branch	Nov. 18, 2021 USD ($)
Business Acquisition [Line Items]
Shares issued (in shares) | shares	18,275,074
Payments to acquire businesses, gross	$ 1,393,508.9
Stock issued for acquisition	$ 464,900,000		$ 464,918,000
Number of bank branches acquired | branch						35
Assets acquired, after acquisition method adjustments						$ 3,110,000,000
Loans acquired, after acquisition method adjustments					$ 0	2,290,000,000	$ 35,200,000
Customer deposits acquired, after acquisition method adjustments						$ 2,720,000,000
Goodwill acquired		$ 174,146,000
Acquisition-related costs				$ 18,700,000