Premises and Equipment and Leases Premises and Equipment and Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Premises and Equipment [Line Items]
Premises and equipment	$ 924,298	$ 843,041
Less accumulated depreciation	350,150	291,733
Premises and equipment, net of accumulated depreciation	574,148	551,308
Depreciation Expense	$ 63,400	54,300	$ 51,600
Lease, Cost [Abstract]
Operating Lease, Weighted Average Remaining Lease Term	10 years 10 months 24 days
Operating Lease, Weighted Average Discount Rate, Percent	2.90%
Operating Lease, costs recognized as occupancy and equipment expense	$ 23,400	25,000	24,200
Operating Lease, operating cash flows	25,300	25,600
Lease, Cost	35,800	42,000	43,000
Short-term Lease, Cost	11,500	13,400	$ 12,600
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Operating Leases, Payments Due, 2022	23,800
Operating Leases, Payments, 2023	24,700
Operating Leases, Payments, 2024	24,300
Operating Leases, Payments, 2025	23,600
Operating Lease, Payments, 2026	22,600
Operating Leases, Payments, 2027 and later	130,000
Premises and equipment, net
Premises and Equipment [Line Items]
Operating Lease, Right-of-Use Asset	181,000	166,000
Lease, Cost [Abstract]
Operating Lease, Right-of-Use Asset	181,000	166,000
Land
Premises and Equipment [Line Items]
Premises and equipment	69,776	69,776
Buildings and improvements
Premises and Equipment [Line Items]
Premises and equipment	472,450	440,528
Software and related integration
Premises and Equipment [Line Items]
Premises and equipment	159,063	120,444
Furniture and equipment
Premises and Equipment [Line Items]
Premises and equipment	186,092	165,344
Construction in progress
Premises and Equipment [Line Items]
Premises and equipment	$ 36,917	$ 46,949