Loans and Leases (Loans and Leases Outstanding) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Loans and leases, not acquired in a transfer accounted for as debt securities	$ 28,680,607	$ 28,322,780
Loans acquired with deteriorated credit quality	560,352	558,716
Total loans and leases	29,240,959	28,881,496
Commercial
Loans and leases, not acquired in a transfer accounted for as debt securities	18,886,482	18,552,002
Commercial \| Construction and land development
Loans and leases, not acquired in a transfer accounted for as debt securities	1,014,017	1,013,454
Commercial \| Owner occupied commercial mortgage
Loans and leases, not acquired in a transfer accounted for as debt securities	10,076,132
Commercial \| Non-owner occupied commercial mortgage
Loans and leases, not acquired in a transfer accounted for as debt securities	3,058,235
Commercial \| Commercial and industrial and leases
Loans and leases, not acquired in a transfer accounted for as debt securities	4,738,098	4,403,792
Commercial \| Commercial mortgage
Loans and leases, not acquired in a transfer accounted for as debt securities		12,282,635
Commercial \| Other commercial real estate
Loans and leases, not acquired in a transfer accounted for as debt securities		542,028
Commercial \| Other
Loans and leases, not acquired in a transfer accounted for as debt securities		310,093
Consumer
Loans and leases, not acquired in a transfer accounted for as debt securities	9,794,125	9,770,778
Consumer \| Construction and land development
Loans and leases, not acquired in a transfer accounted for as debt securities	363,190	357,385
Consumer \| Consumer auto
Loans and leases, not acquired in a transfer accounted for as debt securities	1,201,152
Consumer \| Residential mortgage
Loans and leases, not acquired in a transfer accounted for as debt securities	5,299,412	5,293,917
Consumer \| Revolving mortgage
Loans and leases, not acquired in a transfer accounted for as debt securities	2,362,644
Consumer \| Consumer other
Loans and leases, not acquired in a transfer accounted for as debt securities	$ 567,727
Consumer \| Consumer
Loans and leases, not acquired in a transfer accounted for as debt securities		$ 1,780,404

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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118938799&loc=d3e13503-111538

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=118939070&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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522

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