Loans Composition (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 23,947,536	$ 24,451,724
Interest receivable	81,797	90,263
Loans and Finance Receivables [Member]
Loans and Leases Receivable Disclosure [Line Items]
Interest receivable	59,000	66,000
PPP
Loans and Leases Receivable Disclosure [Line Items]
Loans	405,482	767,757
Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Loans	7,909,119	7,701,422
Commercial real estate — owner occupied
Loans and Leases Receivable Disclosure [Line Items]
Loans	880,755	900,912
Commercial and business lending
Loans and Leases Receivable Disclosure [Line Items]
Loans	9,195,355	9,370,091
Commercial real estate — investor
Loans and Leases Receivable Disclosure [Line Items]
Loans	4,300,651	4,342,584
Real estate construction
Loans and Leases Receivable Disclosure [Line Items]
Loans	1,880,897	1,840,417
Commercial real estate lending
Loans and Leases Receivable Disclosure [Line Items]
Loans	6,181,549	6,183,001
Total commercial
Loans and Leases Receivable Disclosure [Line Items]
Loans	15,376,904	15,553,091
Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Loans	7,638,372	7,878,324
Home equity
Loans and Leases Receivable Disclosure [Line Items]
Loans	631,783	707,255
Other consumer
Loans and Leases Receivable Disclosure [Line Items]
Loans	300,477	313,054
Total consumer
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 8,570,632	$ 8,898,632

Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
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