Business Combinations (Details) $ in Thousands		3 Months Ended	9 Months Ended
	Aug. 01, 2024 USD ($) branch shares	Sep. 30, 2024 USD ($)	Sep. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Apr. 03, 2023 USD ($)
Business Acquisition [Line Items]
Assets		$ 63,788,424	$ 63,788,424	$ 56,259,934	$ 55,555,246
Deposits		51,404,966	51,404,966	45,397,170	44,992,686
Goodwill		800,780	800,780	$ 656,672	$ 656,109
Macatawa Bank Corporation
Business Acquisition [Line Items]
Assets	$ 2,700,000
Deposits	2,300,000
Loan	$ 1,300,000
Macatawa Bank Corporation
Business Acquisition [Line Items]
Business acquisition, number of shares issued (in shares) | shares	4,700,000
Fair value of consideration paid	$ 499,300
Business combination, number of acquired operating branches | branch	26
Business combination, discount on acquired loans	$ 53,700
Business combination, discount on securities	33,500
Business combination, intangible assets acquired	$ 251,900
Acquisition expenses		$ 1,600	$ 2,500
Macatawa Bank Corporation | Macatawa Bank Corporation
Business Acquisition [Line Items]
Number of common stock shares issued for each share of acquiree stock (in shares) | shares	0.137
Rothschild & Co Asset Management U.S.
Business Acquisition [Line Items]
Assets acquired in acquisition						$ 12,600
Goodwill						$ 2,600