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Allowance for Loan and Lease Losses (Summary of Activity In Allowance for Loan and Lease Losses) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Dec. 31, 2016
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Net loans and leases |  |  |  |  | $ 24,667,150 | $ 23,374,932 |  |
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract] |  |  |  |  |  |  |  |
Loans and leases acquired with deteriorated credit quality |  |  |  |  | 638,018 | 762,998 | $ 834,167 | $ 809,169
Commercial |  |  |  |  |  |  |  |
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract] |  |  |  |  |  |  |  |
Loans and leases acquired with deteriorated credit quality |  |  |  |  | 317,014 | 393,419 |  |
Noncommercial |  |  |  |  |  |  |  |
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract] |  |  |  |  |  |  |  |
Loans and leases acquired with deteriorated credit quality |  |  |  |  | 321,004 |  |  |
Noncommercial | Mortgage |  |  |  |  |  |  |  |
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract] |  |  |  |  |  |  |  |
Loans and leases acquired with deteriorated credit quality |  |  |  |  |  | 369,579 |  |
Non-PCI Loans |  |  |  |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |  |  |  |
Impaired Financing Receivable, Related Allowance |  |  |  |  | 11,425 | 9,728 |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | $ 212,442 | $ 215,302 | $ 211,867 | $ 205,026 |  |  |  |
Provision for Loan, Lease, and Other Losses | 2,354 | 8,483 | 15,883 | 29,311 |  |  |  |
Charge-offs | (9,447) | (8,494) | (28,739) | (26,688) |  |  |  |
Recoveries | 2,939 | 3,592 | 9,277 | 11,234 |  |  |  |
Ending balance | 208,288 | 218,883 | 208,288 | 218,883 |  |  |  |
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Loans and leases individually evaluated for impairment |  |  |  |  | 154,676 | 155,646 |  |
Loans and leases collectively evaluated for impairment |  |  |  |  | 24,093,653 | 22,678,181 |  |
Net loans and leases |  |  |  |  | 24,248,329 | 22,833,827 |  |
ALLL for loans and leases individually evaluated for impairment |  |  |  |  | 11,425 | 9,728 |  |
ALLL for loans and leases collectively evaluated for impairment |  |  |  |  | 196,863 | 202,139 |  |
Total allowance for loan and lease losses | 212,442 | 215,302 | 211,867 | 205,026 | 208,288 | 211,867 | 218,883 | 205,026
Non-PCI Loans | Commercial | Construction and land development |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 23,664 | 33,559 | 24,470 | 28,877 |  |  |  |
Provision for Loan, Lease, and Other Losses | 8,702 | (5,150) | 7,788 | (242) |  |  |  |
Charge-offs | (35) | (9) | (43) | (499) |  |  |  |
Recoveries | 136 | 56 | 252 | 320 |  |  |  |
Ending balance | 32,467 | 28,456 | 32,467 | 28,456 |  |  |  |
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Loans and leases individually evaluated for impairment |  |  |  |  | 2,175 | 788 |  |
Loans and leases collectively evaluated for impairment |  |  |  |  | 677,028 | 668,427 |  |
Net loans and leases |  |  |  |  | 679,203 | 669,215 |  |
ALLL for loans and leases individually evaluated for impairment |  |  |  |  | 296 | 185 |  |
ALLL for loans and leases collectively evaluated for impairment |  |  |  |  | 32,171 | 24,285 |  |
Total allowance for loan and lease losses | 23,664 | 33,559 | 24,470 | 28,877 | 32,467 | 24,470 | 28,456 | 28,877
Non-PCI Loans | Commercial | Mortgage |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 44,465 | 49,746 | 45,005 | 48,278 |  |  |  |
Provision for Loan, Lease, and Other Losses | (2,870) | (71) | (3,369) | 574 |  |  |  |
Charge-offs | (606) | (39) | (1,111) | (311) |  |  |  |
Recoveries | 99 | 1,446 | 563 | 2,541 |  |  |  |
Ending balance | 41,088 | 51,082 | 41,088 | 51,082 |  |  |  |
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Loans and leases individually evaluated for impairment |  |  |  |  | 63,412 | 73,655 |  |
Loans and leases collectively evaluated for impairment |  |  |  |  | 10,422,960 | 9,655,367 |  |
Net loans and leases |  |  |  |  | 10,486,372 | 9,729,022 |  |
ALLL for loans and leases individually evaluated for impairment |  |  |  |  | 2,983 | 3,648 |  |
ALLL for loans and leases collectively evaluated for impairment |  |  |  |  | 38,105 | 41,357 |  |
Total allowance for loan and lease losses | 44,465 | 49,746 | 45,005 | 48,278 | 41,088 | 45,005 | 51,082 | 48,278
Non-PCI Loans | Commercial | Other commercial real estate |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 3,823 | 3,612 | 4,571 | 3,269 |  |  |  |
Provision for Loan, Lease, and Other Losses | (1,219) | 891 | (2,044) | 1,228 |  |  |  |
Charge-offs | 0 | 0 | (69) | (5) |  |  |  |
Recoveries | 1 | 8 | 147 | 19 |  |  |  |
Ending balance | 2,605 | 4,511 | 2,605 | 4,511 |  |  |  |
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Loans and leases individually evaluated for impairment |  |  |  |  | 929 | 1,857 |  |
Loans and leases collectively evaluated for impairment |  |  |  |  | 470,603 | 471,576 |  |
Net loans and leases |  |  |  |  | 471,532 | 473,433 |  |
ALLL for loans and leases individually evaluated for impairment |  |  |  |  | 46 | 209 |  |
ALLL for loans and leases collectively evaluated for impairment |  |  |  |  | 2,559 | 4,362 |  |
Total allowance for loan and lease losses | 3,823 | 3,612 | 4,571 | 3,269 | 2,605 | 4,571 | 4,511 | 3,269
Non-PCI Loans | Commercial | Commercial and industrial |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 57,330 | 51,068 | 53,697 | 50,225 |  |  |  |
Provision for Loan, Lease, and Other Losses | (9,271) | 5,621 | (4,026) | 10,181 |  |  |  |
Charge-offs | (1,256) | (1,275) | (4,725) | (7,649) |  |  |  |
Recoveries | 494 | 433 | 2,351 | 3,090 |  |  |  |
Ending balance | 47,297 | 55,847 | 47,297 | 55,847 |  |  |  |
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Loans and leases individually evaluated for impairment |  |  |  |  | 9,048 | 7,974 |  |
Loans and leases collectively evaluated for impairment |  |  |  |  | 3,180,289 | 2,722,433 |  |
Net loans and leases |  |  |  |  | 3,189,337 | 2,730,407 |  |
ALLL for loans and leases individually evaluated for impairment |  |  |  |  | 1,133 | 665 |  |
ALLL for loans and leases collectively evaluated for impairment |  |  |  |  | 46,164 | 53,032 |  |
Total allowance for loan and lease losses | 57,330 | 51,068 | 53,697 | 50,225 | 47,297 | 53,697 | 55,847 | 50,225
Non-PCI Loans | Commercial | Lease financing |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 3,981 | 6,404 | 6,127 | 5,907 |  |  |  |
Provision for Loan, Lease, and Other Losses | 4,011 | 884 | 3,119 | 1,645 |  |  |  |
Charge-offs | (850) | (687) | (2,149) | (957) |  |  |  |
Recoveries | 3 | 3 | 48 | 9 |  |  |  |
Ending balance | 7,145 | 6,604 | 7,145 | 6,604 |  |  |  |
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Loans and leases individually evaluated for impairment |  |  |  |  | 1,042 | 1,914 |  |
Loans and leases collectively evaluated for impairment |  |  |  |  | 615,909 | 892,887 |  |
Net loans and leases |  |  |  |  | 616,951 | 894,801 |  |
ALLL for loans and leases individually evaluated for impairment |  |  |  |  | 135 | 397 |  |
ALLL for loans and leases collectively evaluated for impairment |  |  |  |  | 7,010 | 5,730 |  |
Total allowance for loan and lease losses | 3,981 | 6,404 | 6,127 | 5,907 | 7,145 | 6,127 | 6,604 | 5,907
Non-PCI Loans | Commercial | Other |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 4,691 | 3,302 | 4,689 | 3,127 |  |  |  |
Provision for Loan, Lease, and Other Losses | (2,404) | 58 | (2,403) | 299 |  |  |  |
Charge-offs | (56) | (666) | (98) | (853) |  |  |  |
Recoveries | 117 | 123 | 160 | 244 |  |  |  |
Ending balance | 2,348 | 2,817 | 2,348 | 2,817 |  |  |  |
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Loans and leases individually evaluated for impairment |  |  |  |  | 241 | 521 |  |
Loans and leases collectively evaluated for impairment |  |  |  |  | 296,747 | 301,655 |  |
Net loans and leases |  |  |  |  | 296,988 | 302,176 |  |
ALLL for loans and leases individually evaluated for impairment |  |  |  |  | 18 | 0 |  |
ALLL for loans and leases collectively evaluated for impairment |  |  |  |  | 2,330 | 4,689 |  |
Total allowance for loan and lease losses | 4,691 | 3,302 | 4,689 | 3,127 | 2,348 | 4,689 | 2,817 | 3,127
Non-PCI Loans | Noncommercial | Construction and land development |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 4,027 | 1,503 | 3,962 | 1,596 |  |  |  |
Provision for Loan, Lease, and Other Losses | (1,203) | 92 | (1,046) | (1) |  |  |  |
Charge-offs | 0 | 0 | (219) | 0 |  |  |  |
Recoveries | 0 | 0 | 127 | 0 |  |  |  |
Ending balance | 2,824 | 1,595 | 2,824 | 1,595 |  |  |  |
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Loans and leases individually evaluated for impairment |  |  |  |  | 4,236 | 4,551 |  |
Loans and leases collectively evaluated for impairment |  |  |  |  | 237,200 | 243,738 |  |
Net loans and leases |  |  |  |  | 241,436 | 248,289 |  |
ALLL for loans and leases individually evaluated for impairment |  |  |  |  | 501 | 68 |  |
ALLL for loans and leases collectively evaluated for impairment |  |  |  |  | 2,323 | 3,894 |  |
Total allowance for loan and lease losses | 4,027 | 1,503 | 3,962 | 1,596 | 2,824 | 3,962 | 1,595 | 1,596
Non-PCI Loans | Noncommercial | Mortgage |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 17,802 | 15,843 | 15,706 | 14,447 |  |  |  |
Provision for Loan, Lease, and Other Losses | (1,828) | 531 | 1,176 | 2,037 |  |  |  |
Charge-offs | (360) | (604) | (1,455) | (1,076) |  |  |  |
Recoveries | 128 | 92 | 315 | 454 |  |  |  |
Ending balance | 15,742 | 15,862 | 15,742 | 15,862 |  |  |  |
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Loans and leases individually evaluated for impairment |  |  |  |  | 42,617 | 37,842 |  |
Loans and leases collectively evaluated for impairment |  |  |  |  | 4,030,618 | 3,485,944 |  |
Net loans and leases |  |  |  |  | 4,073,235 | 3,523,786 |  |
ALLL for loans and leases individually evaluated for impairment |  |  |  |  | 2,791 | 2,733 |  |
ALLL for loans and leases collectively evaluated for impairment |  |  |  |  | 12,951 | 12,973 |  |
Total allowance for loan and lease losses | 17,802 | 15,843 | 15,706 | 14,447 | 15,742 | 15,706 | 15,862 | 14,447
Non-PCI Loans | Noncommercial | Revolving mortgage |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 21,886 | 22,465 | 22,436 | 21,013 |  |  |  |
Provision for Loan, Lease, and Other Losses | 465 | 842 | 1,220 | 2,446 |  |  |  |
Charge-offs | (759) | (218) | (2,778) | (1,323) |  |  |  |
Recoveries | 712 | 228 | 1,426 | 1,181 |  |  |  |
Ending balance | 22,304 | 23,317 | 22,304 | 23,317 |  |  |  |
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Loans and leases individually evaluated for impairment |  |  |  |  | 28,089 | 23,770 |  |
Loans and leases collectively evaluated for impairment |  |  |  |  | 2,542,007 | 2,677,755 |  |
Net loans and leases |  |  |  |  | 2,570,096 | 2,701,525 |  |
ALLL for loans and leases individually evaluated for impairment |  |  |  |  | 2,759 | 1,085 |  |
ALLL for loans and leases collectively evaluated for impairment |  |  |  |  | 19,545 | 21,351 |  |
Total allowance for loan and lease losses | 21,886 | 22,465 | 22,436 | 21,013 | 22,304 | 22,436 | 23,317 | 21,013
Non-PCI Loans | Noncommercial | Consumer |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 30,773 | 27,800 | 31,204 | 28,287 |  |  |  |
Provision for Loan, Lease, and Other Losses | 7,971 | 4,785 | 15,468 | 11,144 |  |  |  |
Charge-offs | (5,525) | (4,996) | (16,092) | (14,015) |  |  |  |
Recoveries | 1,249 | 1,203 | 3,888 | 3,376 |  |  |  |
Ending balance | 34,468 | 28,792 | 34,468 | 28,792 |  |  |  |
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Loans and leases individually evaluated for impairment |  |  |  |  | 2,887 | 2,774 |  |
Loans and leases collectively evaluated for impairment |  |  |  |  | 1,620,292 | 1,558,399 |  |
Net loans and leases |  |  |  |  | 1,623,179 | 1,561,173 |  |
ALLL for loans and leases individually evaluated for impairment |  |  |  |  | 763 | 738 |  |
ALLL for loans and leases collectively evaluated for impairment |  |  |  |  | 33,705 | 30,466 |  |
Total allowance for loan and lease losses | 30,773 | 27,800 | 31,204 | 28,287 | 34,468 | 31,204 | 28,792 | 28,287
PCI Loans |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 12,423 | 13,496 | 10,026 | 13,769 |  |  |  |
Provision for Loan, Lease, and Other Losses | (1,514) | (537) | 1,000 | (810) |  |  |  |
Charge-offs | 0 | 0 | (117) | 0 |  |  |  |
Recoveries | 0 | 0 | 0 | 0 |  |  |  |
Ending balance | 10,909 | 12,959 | 10,909 | 12,959 |  |  |  |
Allowance for Loans and Leases Evaluated for Impairment [Abstract] |  |  |  |  |  |  |  |
Total allowance for loan and lease losses | $ 12,423 | $ 13,496 | $ 10,026 | $ 13,769 | 10,909 | 10,026 | $ 12,959 | $ 13,769
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract] |  |  |  |  |  |  |  |
Loans and leases acquired with deteriorated credit quality |  |  |  |  | $ 638,018 | $ 762,998 |  |

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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=82894507&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=82894903&loc=d3e15032-111544 + Details
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- Definition The balance of financing receivables that were collectively evaluated for impairment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
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- Definition Amount after allowance and 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 and loans held for sale. + 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=82891408&loc=d3e4428-111522 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.7) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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