Allowance for Credit Losses - Credit Risk Profiles by Internally Assigned Grade (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Credit quality
Loans and leases	$ 12,961,999	$ 13,279,097	$ 13,211,650
Loss
Credit quality
Loans and leases	0	0
Commercial and Industrial
Credit quality
Loans and leases	2,087,099	3,019,507	2,743,242
Commercial and Industrial | Pass
Credit quality
Loans and leases	1,947,671	2,685,883
Commercial and Industrial | Special mention
Credit quality
Loans and leases	33,621	164,897
Commercial and Industrial | Substandard
Credit quality
Loans and leases	27,517	75,273
Commercial real estate
Credit quality
Loans and leases	3,639,623	3,392,676	3,463,953
Commercial real estate | Pass
Credit quality
Loans and leases	3,502,424	3,100,309
Commercial real estate | Special mention
Credit quality
Loans and leases	119,337	226,905
Commercial real estate | Substandard
Credit quality
Loans and leases	17,702	64,964
Construction
Credit quality
Loans and leases	813,969	735,819	519,241
Construction | Pass
Credit quality
Loans and leases	761,600	667,354
Construction | Special mention
Credit quality
Loans and leases	1,307	15,104
Construction | Substandard
Credit quality
Loans and leases	1,202	3,891
Lease financing
Credit quality
Loans and leases	231,394	245,411	$ 202,483
Lease financing | Pass
Credit quality
Loans and leases	224,454	234,933
Lease financing | Special mention
Credit quality
Loans and leases	5,173	4,099
Lease financing | Substandard
Credit quality
Loans and leases	1,767	6,379
Commercial Lending
Credit quality
Loans and leases	$ 6,772,085	$ 7,393,413