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Allowance for Credit Losses - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Line Items]
Accrued interest related to financial assets held at amortized cost	$ 351,500	$ 290,900	$ 351,500	$ 290,900	$ 304,500
Financial Asset, Amortized Cost, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Accrued interest receivable and other	Accrued interest receivable and other	Accrued interest receivable and other	Accrued interest receivable and other	Accrued interest receivable and other
Nonaccrual loans with no related allowance for credit losses	$ 62,700		$ 62,700
Provision for credit losses	22,300	$ 19,948	83,900	$ 71,589
Provision for credit losses - Day 1 on non-PCD assets acquired during the period	15,547		15,547
Loan net charge-offs	26,700		78,500
Provision for credit losses	(12)		132
Foreclosed residential real estate properties	0		0
Commitments to lend	8,600	45,000	8,600	45,000
Macatawa Bank Corporation
Financing Receivable, Allowance for Credit Loss [Line Items]
Provision for credit losses - Day 1 on non-PCD assets acquired during the period	15,500
Home equity
Financing Receivable, Allowance for Credit Loss [Line Items]
Provision for credit losses		307		(338)
Provision for credit losses - Day 1 on non-PCD assets acquired during the period	1,344		1,344
Residential real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Provision for credit losses		484		1,833
Provision for credit losses - Day 1 on non-PCD assets acquired during the period	638		638
Premium finance receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Provision for credit losses		7,776		13,196
Provision for credit losses - Day 1 on non-PCD assets acquired during the period	0		0
Financing Receivable \| Residential Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Recorded investment, foreclosure proceedings in process	$ 40,400	$ 55,100	$ 40,400	$ 55,100