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Loans and Allowances for Credit Losses, Credit Quality Indicators (Details) - USD ($) $ in Thousands | Sep. 30, 2018 | Jun. 30, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Dec. 31, 2016
--- | --- | --- | --- | --- | --- | ---
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | $ 16,533,403 |  | $ 15,297,889 | $ 15,351,135 |  |
Non-Graded, Recorded Investment | 1,816,056 |  | 1,855,535 | 1,855,699 |  |
Total | 18,349,459 |  | 17,153,424 | 17,206,834 |  |
Related Allowance [Abstract] |  |  |  |  |  |
Internally Risk Graded, Allowance | 172,982 |  | 189,412 | 201,362 |  |
Non-Graded, Allowance | 18,697 |  | 19,053 | 18,263 |  |
Total | 210,569 | $ 215,142 | 230,682 | 247,703 | $ 250,061 | $ 246,159
Commercial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 11,549,529 |  | 10,706,035 | 10,750,657 |  |
Non-Graded, Recorded Investment | 26,572 |  | 27,940 | 45,277 |  |
Total | 11,576,101 |  | 10,733,975 | 10,795,934 |  |
Related Allowance [Abstract] |  |  |  |  |  |
Internally Risk Graded, Allowance | 103,185 |  | 123,383 | 135,846 |  |
Non-Graded, Allowance | 913 |  | 886 | 955 |  |
Total | 104,098 | 113,722 | 124,269 | 136,801 | 137,742 | 140,213
Commercial [Member] | Energy [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 3,294,867 |  | 2,930,156 | 2,867,981 |  |
Commercial [Member] | Services [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 3,017,311 |  | 2,986,949 | 2,967,513 |  |
Commercial [Member] | Wholesale/retail [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 1,650,729 |  | 1,471,256 | 1,658,098 |  |
Commercial [Member] | Manufacturing [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 660,582 |  | 496,774 | 519,446 |  |
Commercial [Member] | Healthcare [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 2,437,323 |  | 2,314,753 | 2,239,451 |  |
Commercial [Member] | Other commercial and industrial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 515,289 |  | 534,087 | 543,445 |  |
Commercial real estate [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 3,804,675 |  | 3,479,987 | 3,518,142 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Total | 3,804,675 |  | 3,479,987 | 3,518,142 |  |
Related Allowance [Abstract] |  |  |  |  |  |
Internally Risk Graded, Allowance | 60,189 |  | 56,621 | 56,405 |  |
Non-Graded, Allowance | 0 |  | 0 | 0 |  |
Total | 60,189 | 58,758 | 56,621 | 56,405 | 58,580 | 50,749
Commercial real estate [Member] | Residential construction and land development [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 101,872 |  | 117,245 | 112,102 |  |
Commercial real estate [Member] | Retail [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 759,423 |  | 691,532 | 725,865 |  |
Commercial real estate [Member] | Office [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 824,829 |  | 831,770 | 797,089 |  |
Commercial real estate [Member] | Multifamily [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 1,120,166 |  | 980,017 | 999,009 |  |
Commercial real estate [Member] | Industrial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 696,774 |  | 573,014 | 591,080 |  |
Commercial real estate [Member] | Other commercial real estate [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 301,611 |  | 286,409 | 292,997 |  |
Residential mortgage [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 262,612 |  | 234,477 | 226,306 |  |
Non-Graded, Recorded Investment | 1,709,130 |  | 1,739,209 | 1,719,444 |  |
Total | 1,971,742 |  | 1,973,686 | 1,945,750 |  |
Related Allowance [Abstract] |  |  |  |  |  |
Internally Risk Graded, Allowance | 3,099 |  | 2,947 | 3,068 |  |
Non-Graded, Allowance | 15,584 |  | 15,504 | 15,325 |  |
Total | 18,683 | 18,544 | 18,451 | 18,393 | 18,259 | 18,224
Residential mortgage [Member] | Permanent mortgage [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 1,094,926 |  | 1,043,435 | 1,013,965 |  |
Residential mortgage [Member] | Permanent mortgages guaranteed by US government agencies [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 180,718 |  | 197,506 | 187,370 |  |
Residential mortgage [Member] | Home equity [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Total | 696,098 |  | 732,745 | 744,415 |  |
Personal [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 916,587 |  | 877,390 | 856,030 |  |
Non-Graded, Recorded Investment | 80,354 |  | 88,386 | 90,978 |  |
Total | 996,941 |  | 965,776 | 947,008 |  |
Related Allowance [Abstract] |  |  |  |  |  |
Internally Risk Graded, Allowance | 6,509 |  | 6,461 | 6,043 |  |
Non-Graded, Allowance | 2,200 |  | 2,663 | 1,983 |  |
Total | 8,709 | 8,646 | 9,124 | 8,026 | 8,106 | 8,773
Specific Allowance [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 16,533,403 |  | 15,297,889 | 15,351,135 |  |
Non-Graded, Recorded Investment | 1,816,056 |  | 1,855,535 | 1,855,699 |  |
Total | 18,349,459 |  | 17,153,424 | 17,206,834 |  |
Related Allowance [Abstract] |  |  |  |  |  |
Internally Risk Graded, Allowance | 172,982 |  | 189,412 | 201,362 |  |
Non-Graded, Allowance | 18,697 |  | 19,053 | 18,263 |  |
Total | 191,679 |  | 208,465 | 219,625 |  |
Nonspecific Allowance [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Total | 0 |  | 0 | 0 |  |
Related Allowance [Abstract] |  |  |  |  |  |
Internally Risk Graded, Allowance | 0 |  | 0 | 0 |  |
Non-Graded, Allowance | 0 |  | 0 | 0 |  |
Total | 18,890 | $ 15,472 | 22,217 | 28,078 | $ 27,374 | $ 28,200
Performing [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 1,774,871 |  | 1,808,995 | 1,811,095 |  |
Performing [Member] | Commercial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 26,511 |  | 27,870 | 45,132 |  |
Performing [Member] | Commercial [Member] | Energy [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Commercial [Member] | Services [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Commercial [Member] | Wholesale/retail [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Commercial [Member] | Manufacturing [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Commercial [Member] | Healthcare [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Commercial [Member] | Other commercial and industrial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 26,511 |  | 27,870 | 45,132 |  |
Performing [Member] | Commercial real estate [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Commercial real estate [Member] | Residential construction and land development [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Commercial real estate [Member] | Retail [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Commercial real estate [Member] | Office [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Commercial real estate [Member] | Multifamily [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Commercial real estate [Member] | Industrial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Commercial real estate [Member] | Other commercial real estate [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Residential mortgage [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 1,668,199 |  | 1,692,925 | 1,675,154 |  |
Performing [Member] | Residential mortgage [Member] | Permanent mortgage [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 810,445 |  | 784,928 | 764,252 |  |
Performing [Member] | Residential mortgage [Member] | Permanent mortgages guaranteed by US government agencies [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 172,928 |  | 188,327 | 178,479 |  |
Performing [Member] | Residential mortgage [Member] | Home equity [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 684,826 |  | 719,670 | 732,423 |  |
Performing [Member] | Personal [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Non-Graded, Recorded Investment | 80,161 |  | 88,200 | 90,809 |  |
Performing [Member] | Pass [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 16,189,884 |  | 14,797,279 | 14,687,428 |  |
Performing [Member] | Pass [Member] | Commercial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 11,242,901 |  | 10,226,089 | 10,102,018 |  |
Performing [Member] | Pass [Member] | Commercial [Member] | Energy [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 3,127,227 |  | 2,632,986 | 2,436,465 |  |
Performing [Member] | Pass [Member] | Commercial [Member] | Services [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 2,974,082 |  | 2,943,869 | 2,932,577 |  |
Performing [Member] | Pass [Member] | Commercial [Member] | Wholesale/retail [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 1,636,405 |  | 1,443,917 | 1,637,698 |  |
Performing [Member] | Pass [Member] | Commercial [Member] | Manufacturing [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 631,198 |  | 472,869 | 486,383 |  |
Performing [Member] | Pass [Member] | Commercial [Member] | Healthcare [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 2,402,801 |  | 2,253,497 | 2,150,099 |  |
Performing [Member] | Pass [Member] | Commercial [Member] | Other commercial and industrial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 471,188 |  | 478,951 | 458,796 |  |
Performing [Member] | Pass [Member] | Commercial real estate [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 3,771,447 |  | 3,463,002 | 3,505,318 |  |
Performing [Member] | Pass [Member] | Commercial real estate [Member] | Residential construction and land development [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 99,694 |  | 113,190 | 110,178 |  |
Performing [Member] | Pass [Member] | Commercial real estate [Member] | Retail [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 737,313 |  | 686,915 | 724,887 |  |
Performing [Member] | Pass [Member] | Commercial real estate [Member] | Office [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 817,854 |  | 824,408 | 788,539 |  |
Performing [Member] | Pass [Member] | Commercial real estate [Member] | Multifamily [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 1,120,145 |  | 979,969 | 998,125 |  |
Performing [Member] | Pass [Member] | Commercial real estate [Member] | Industrial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 695,554 |  | 573,014 | 591,080 |  |
Performing [Member] | Pass [Member] | Commercial real estate [Member] | Other commercial real estate [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 300,887 |  | 285,506 | 292,509 |  |
Performing [Member] | Pass [Member] | Residential mortgage [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 259,106 |  | 232,492 | 224,235 |  |
Performing [Member] | Pass [Member] | Residential mortgage [Member] | Permanent mortgage [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 259,106 |  | 232,492 | 224,235 |  |
Performing [Member] | Pass [Member] | Residential mortgage [Member] | Permanent mortgages guaranteed by US government agencies [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Pass [Member] | Residential mortgage [Member] | Home equity [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Pass [Member] | Personal [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 916,430 |  | 875,696 | 855,857 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 55,727 |  | 118,175 | 197,952 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 46,342 |  | 103,324 | 188,546 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] | Energy [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 7,233 |  | 60,288 | 114,065 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] | Services [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 27,337 |  | 13,927 | 26,372 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] | Wholesale/retail [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 1,508 |  | 19,263 | 9,021 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] | Manufacturing [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 7,265 |  | 6,653 | 7,181 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] | Healthcare [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 2,614 |  | 3,186 | 31,855 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] | Other commercial and industrial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 385 |  | 7 | 52 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 9,338 |  | 13,303 | 8,964 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate [Member] | Residential construction and land development [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 1,828 |  | 1,828 | 0 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate [Member] | Retail [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 4,243 | 689 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate [Member] | Office [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 6,975 |  | 7,087 | 8,275 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate [Member] | Multifamily [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate [Member] | Industrial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate [Member] | Other commercial real estate [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 535 |  | 145 | 0 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Residential mortgage [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 393 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Residential mortgage [Member] | Permanent mortgage [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 393 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Residential mortgage [Member] | Permanent mortgages guaranteed by US government agencies [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Residential mortgage [Member] | Home equity [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Other Loans Especially Mentioned [Member] | Personal [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 47 |  | 1,548 | 49 |  |
Performing [Member] | Substandard [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 175,985 |  | 241,101 | 284,723 |  |
Performing [Member] | Substandard [Member] | Commercial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 150,857 |  | 239,389 | 283,338 |  |
Performing [Member] | Substandard [Member] | Commercial [Member] | Energy [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 106,374 |  | 144,598 | 206,768 |  |
Performing [Member] | Substandard [Member] | Commercial [Member] | Services [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 11,795 |  | 26,533 | 7,390 |  |
Performing [Member] | Substandard [Member] | Commercial [Member] | Wholesale/retail [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 3,567 |  | 5,502 | 9,486 |  |
Performing [Member] | Substandard [Member] | Commercial [Member] | Manufacturing [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 12,917 |  | 11,290 | 16,823 |  |
Performing [Member] | Substandard [Member] | Commercial [Member] | Healthcare [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 16,204 |  | 43,305 | 33,051 |  |
Performing [Member] | Substandard [Member] | Commercial [Member] | Other commercial and industrial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 8,161 | 9,820 |  |
Performing [Member] | Substandard [Member] | Commercial real estate [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 22,574 |  | 827 | 885 |  |
Performing [Member] | Substandard [Member] | Commercial real estate [Member] | Residential construction and land development [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 395 | 0 |  |
Performing [Member] | Substandard [Member] | Commercial real estate [Member] | Retail [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 21,333 |  | 98 | 0 |  |
Performing [Member] | Substandard [Member] | Commercial real estate [Member] | Office [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Substandard [Member] | Commercial real estate [Member] | Multifamily [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 21 |  | 48 | 884 |  |
Performing [Member] | Substandard [Member] | Commercial real estate [Member] | Industrial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 1,220 |  | 0 | 0 |  |
Performing [Member] | Substandard [Member] | Commercial real estate [Member] | Other commercial real estate [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 286 | 1 |  |
Performing [Member] | Substandard [Member] | Residential mortgage [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 2,520 |  | 822 | 462 |  |
Performing [Member] | Substandard [Member] | Residential mortgage [Member] | Permanent mortgage [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 2,520 |  | 822 | 462 |  |
Performing [Member] | Substandard [Member] | Residential mortgage [Member] | Permanent mortgages guaranteed by US government agencies [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Substandard [Member] | Residential mortgage [Member] | Home equity [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Performing [Member] | Substandard [Member] | Personal [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 34 |  | 63 | 38 |  |
Nonaccrual [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 111,807 |  | 141,334 | 181,032 |  |
Non-Graded, Recorded Investment | 41,185 |  | 46,540 | 44,604 |  |
Nonaccrual [Member] | Commercial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 109,429 |  | 137,233 | 176,755 |  |
Non-Graded, Recorded Investment | 61 |  | 70 | 145 |  |
Nonaccrual [Member] | Commercial [Member] | Energy [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 54,033 |  | 92,284 | 110,683 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Nonaccrual [Member] | Commercial [Member] | Services [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 4,097 |  | 2,620 | 1,174 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Nonaccrual [Member] | Commercial [Member] | Wholesale/retail [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 9,249 |  | 2,574 | 1,893 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Nonaccrual [Member] | Commercial [Member] | Manufacturing [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 9,202 |  | 5,962 | 9,059 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Nonaccrual [Member] | Commercial [Member] | Healthcare [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 15,704 |  | 14,765 | 24,446 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Nonaccrual [Member] | Commercial [Member] | Other commercial and industrial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 17,144 |  | 19,028 | 29,500 |  |
Non-Graded, Recorded Investment | 61 |  | 70 | 145 |  |
Nonaccrual [Member] | Commercial real estate [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 1,316 |  | 2,855 | 2,975 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Nonaccrual [Member] | Commercial real estate [Member] | Residential construction and land development [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 350 |  | 1,832 | 1,924 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Nonaccrual [Member] | Commercial real estate [Member] | Retail [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 777 |  | 276 | 289 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Nonaccrual [Member] | Commercial real estate [Member] | Office [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 275 | 275 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Nonaccrual [Member] | Commercial real estate [Member] | Multifamily [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Nonaccrual [Member] | Commercial real estate [Member] | Industrial [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Nonaccrual [Member] | Commercial real estate [Member] | Other commercial real estate [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 189 |  | 472 | 487 |  |
Non-Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Nonaccrual [Member] | Residential mortgage [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 986 |  | 1,163 | 1,216 |  |
Non-Graded, Recorded Investment | 40,931 |  | 46,284 | 44,290 |  |
Nonaccrual [Member] | Residential mortgage [Member] | Permanent mortgage [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 986 |  | 1,163 | 1,216 |  |
Non-Graded, Recorded Investment | 21,869 |  | 24,030 | 23,407 |  |
Nonaccrual [Member] | Residential mortgage [Member] | Permanent mortgages guaranteed by US government agencies [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Non-Graded, Recorded Investment | 7,790 |  | 9,179 | 8,891 |  |
Nonaccrual [Member] | Residential mortgage [Member] | Home equity [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 0 |  | 0 | 0 |  |
Non-Graded, Recorded Investment | 11,272 |  | 13,075 | 11,992 |  |
Nonaccrual [Member] | Personal [Member] |  |  |  |  |  |
Recorded Investment [Abstract] |  |  |  |  |  |
Internally Risk Graded, Recorded Investment | 76 |  | 83 | 86 |  |
Non-Graded, Recorded Investment | $ 193 |  | $ 186 | $ 169 |  |

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