Acquisition Activity - Additional Information (Details) $ in Thousands			3 Months Ended
	Feb. 15, 2022 USD ($) shares	May 30, 2021	Mar. 31, 2022 USD ($)
Business Acquisition [Line Items]
Purchase price of loans at acquisition			$ 1,400,831
Par value of acquired loans at acquisition			1,488,365
Allowance for credit losses at acquisition			78,531
Accumulated benefit obligation			60,200
Plan assets			77,200
Series A Preferred Stock
Business Acquisition [Line Items]
Shares issued for acquisition (in shares) | shares	108,000
Series C Preferred Stock
Business Acquisition [Line Items]
Shares issued for acquisition (in shares) | shares	122,500
Depositary Shares, each representing a 1/40th interest in a share of Non-Cumulative Perpetual Preferred Stock, Series A
Business Acquisition [Line Items]
Shares issued for acquisition (in shares) | shares	4,320,000
Depositary Shares, each representing a 1/40th interest in a share of Non-Cumulative Perpetual Preferred Stock, Series C
Business Acquisition [Line Items]
Shares issued for acquisition (in shares) | shares	4,900,000
First Midwest
Business Acquisition [Line Items]
Shares exchange ratio		1.1336
Other intangible assets	$ 117,584
Transaction costs, expensed			41,300
Transaction costs			41,300
Increase in allowance for loan loss			96,300
Transaction value	2,690,182
First Midwest | Unfunded Loan Commitment
Business Acquisition [Line Items]
Increase in allowance for loan loss			$ 11,000
First Midwest | Core deposit
Business Acquisition [Line Items]
Other intangible assets	$ 77,900
Estimated useful lives	10 years
First Midwest | Customer trust relationships
Business Acquisition [Line Items]
Other intangible assets	$ 39,700
Estimated useful lives	13 years
First Midwest | Series A Preferred Stock
Business Acquisition [Line Items]
Dividend rate		7.00%
First Midwest | Series C Preferred Stock
Business Acquisition [Line Items]
Dividend rate		7.00%