Other Assets - Software, Net (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total capitalized implementation costs	$ 0	$ 0
Capitalized internal-use software, accumulated amortization	28,700,000	39,800,000
Capitalized internal-use software, net book value	10,800,000	15,100,000
Hosting arrangements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Accumulated amortization	21,200,000	7,700,000
Net book value	111,400,000	110,500,000
Other noninterest expense
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Amortization expense for all capitalized implementation costs	5,000,000.0	5,400,000	$ 8,600,000
Equipment expense | Hosting arrangements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total amortization expense for all capitalized implementation costs	13,500,000	7,200,000	$ 500,000
Included in other assets
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total capitalized internal-use software	39,500,000	54,900,000
Included in other assets | Hosting arrangements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total capitalized implementation costs	$ 132,600,000	$ 118,200,000