Loans and Leases (Loans and Leases Outstanding) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loans and Leases Receivable, Gross, Carrying Amount, Covered	$ 67,800	$ 84,800
PCI Loans	762,998	809,169	$ 950,516
Non-PCI	22,833,827	20,928,709
Total loans and leases	23,596,825	21,737,878
Commercial
PCI Loans	396,938	499,970
Non-PCI	14,799,054	13,760,703
Commercial \| Construction and land development
PCI Loans	13,654	20,766
Non-PCI	669,215	649,157
Commercial \| Mortgage
PCI Loans	358,103	453,013
Non-PCI	9,729,022	9,026,220
Commercial \| Commercial and industrial
PCI Loans	6,374	11,844
Non-PCI	2,730,407	2,567,501
Commercial \| Lease financing
Non-PCI	894,801	826,270
Commercial \| Other commercial real estate
PCI Loans	17,124	12,645
Non-PCI	473,433	351,291
Commercial \| Other
PCI Loans	1,683	1,702
Non-PCI	302,176	340,264
Noncommercial
PCI Loans	366,060	309,199
Non-PCI	8,034,773	7,168,006
Noncommercial \| Construction and land development
Non-PCI	248,289	231,400
Noncommercial \| Mortgage
Non-PCI	3,523,786	2,889,124
Noncommercial \| Revolving mortgage
Non-PCI	2,701,525	2,601,344
Noncommercial \| Consumer
PCI Loans	2,190	1,772
Non-PCI	$ 1,561,173	$ 1,446,138

All loans and leases, excluding purchased-credit impaired loans accounted for under ASC 310-30.

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- Definition

The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and other-than-temporary impairments), for loans accounted for as debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82894507&loc=d3e13503-111538

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=82894903&loc=d3e15032-111544

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- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

+ Details

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- Definition

Aggregate gross carrying amount of loans and leases receivable covered by loss sharing agreements.

+ References

No definition available.

+ Details

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