Income Taxes - Unrecognized Tax Benefits (Details) - First Midwest - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 11,007	$ 0	$ 0
Additions for acquired uncertain tax positions	0	14,897	0
Additions based on tax positions related to prior years	60	0	0
Reductions for tax positions relating to prior years	0	(2,751)	0
Reductions due to statute of limitations expiring	(1,112)	(1,139)	0
Balance at end of period	$ 9,955	$ 11,007	$ 0