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Loans and Allowance for Credit Losses, Impaired Loans (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2019 | Jun. 30, 2019 | Dec. 31, 2018
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | $ 461,668 |  | $ 461,668 |  | $ 423,787 |
Impaired loans, recorded investment, total |  | 372,409 |  | 372,409 |  | 346,981 |
Impaired loans, recorded investment with no related allowance |  | 363,147 |  | 363,147 |  | 311,526 |
Impaired loans, recorded investment with related allowance |  | 9,262 |  | 9,262 |  | 35,455 |
Impaired loans, related allowance |  | 4,038 |  | 4,038 |  | 8,732 |
Impaired loans, average recorded investment |  | 358,043 |  | 354,305 |  |  |
Impaired loans, interest income recognized |  | 2,254 |  | 4,457 |  |  |
Commercial [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 198,891 |  | 198,891 |  | 156,163 |
Impaired loans, recorded investment, total |  | 123,395 |  | 123,395 |  | 99,841 |
Impaired loans, recorded investment with no related allowance |  | 114,133 |  | 114,133 |  | 64,386 |
Impaired loans, recorded investment with related allowance |  | 9,262 |  | 9,262 |  | 35,455 |
Impaired loans, related allowance |  | 4,038 |  | 4,038 |  | 8,732 |
Impaired loans, average recorded investment |  | 112,049 |  | 105,389 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial [Member] | Energy [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 118,959 |  | 118,959 |  | 79,675 |
Impaired loans, recorded investment, total |  | 71,632 |  | 71,632 |  | 47,494 |
Impaired loans, recorded investment with no related allowance |  | 64,066 |  | 64,066 |  | 18,639 |
Impaired loans, recorded investment with related allowance |  | 7,566 |  | 7,566 |  | 28,855 |
Impaired loans, related allowance |  | 1,175 |  | 1,175 |  | 5,362 |
Impaired loans, average recorded investment |  | 58,185 |  | 59,074 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial [Member] | Services [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 13,343 |  | 13,343 |  | 13,437 |
Impaired loans, recorded investment, total |  | 10,087 |  | 10,087 |  | 8,567 |
Impaired loans, recorded investment with no related allowance |  | 10,061 |  | 10,061 |  | 8,489 |
Impaired loans, recorded investment with related allowance |  | 26 |  | 26 |  | 78 |
Impaired loans, related allowance |  | 26 |  | 26 |  | 74 |
Impaired loans, average recorded investment |  | 10,309 |  | 7,156 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial [Member] | Wholesale/retail [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 1,600 |  | 1,600 |  | 1,722 |
Impaired loans, recorded investment, total |  | 1,390 |  | 1,390 |  | 1,316 |
Impaired loans, recorded investment with no related allowance |  | 1,126 |  | 1,126 |  | 1,015 |
Impaired loans, recorded investment with related allowance |  | 264 |  | 264 |  | 301 |
Impaired loans, related allowance |  | 101 |  | 101 |  | 101 |
Impaired loans, average recorded investment |  | 1,407 |  | 1,030 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial [Member] | Manufacturing [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 8,896 | [1] | 8,896 | [1] | 10,055 |
Impaired loans, recorded investment, total |  | 8,613 | [1] | 8,613 | [1] | 8,919 |
Impaired loans, recorded investment with no related allowance |  | 8,383 | [1] | 8,383 | [1] | 8,673 |
Impaired loans, recorded investment with related allowance |  | 230 | [1] | 230 | [1] | 246 |
Impaired loans, related allowance |  | 236 | [1] | 236 | [1] | 246 |
Impaired loans, average recorded investment | [1] | 9,080 |  | 8,384 |  |  |
Impaired loans, interest income recognized | [1] | 0 |  | 0 |  |  |
Impaired loans, unpaid principal balance to affiliates |  | 4,700 |  | 4,700 |  |  |
Commercial [Member] | Healthcare [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 30,255 |  | 30,255 |  | 24,319 |
Impaired loans, recorded investment, total |  | 16,148 |  | 16,148 |  | 16,538 |
Impaired loans, recorded investment with no related allowance |  | 14,972 |  | 14,972 |  | 10,563 |
Impaired loans, recorded investment with related allowance |  | 1,176 |  | 1,176 |  | 5,975 |
Impaired loans, related allowance |  | 2,500 |  | 2,500 |  | 2,949 |
Impaired loans, average recorded investment |  | 17,441 |  | 13,632 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial [Member] | Public finance [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 0 |  | 0 |  | 0 |
Impaired loans, recorded investment, total |  | 0 |  | 0 |  | 0 |
Impaired loans, recorded investment with no related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, average recorded investment |  |  |  | 0 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial [Member] | Other commercial and industrial [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 25,838 |  | 25,838 |  | 26,955 |
Impaired loans, recorded investment, total |  | 15,525 |  | 15,525 |  | 17,007 |
Impaired loans, recorded investment with no related allowance |  | 15,525 |  | 15,525 |  | 17,007 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, average recorded investment |  | 15,627 |  | 16,113 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial real estate [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 23,109 |  | 23,109 |  | 30,138 |
Impaired loans, recorded investment, total |  | 21,670 |  | 21,670 |  | 21,621 |
Impaired loans, recorded investment with no related allowance |  | 21,670 |  | 21,670 |  | 21,621 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, average recorded investment |  | 21,590 |  | 21,645 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial real estate [Member] | Residential construction and land development [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 1,306 |  | 1,306 |  | 1,306 |
Impaired loans, recorded investment, total |  | 350 |  | 350 |  | 350 |
Impaired loans, recorded investment with no related allowance |  | 350 |  | 350 |  | 350 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, average recorded investment |  | 350 |  | 350 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial real estate [Member] | Retail [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 20,380 |  | 20,380 |  | 27,680 |
Impaired loans, recorded investment, total |  | 20,057 |  | 20,057 |  | 20,279 |
Impaired loans, recorded investment with no related allowance |  | 20,057 |  | 20,057 |  | 20,279 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, average recorded investment |  | 20,108 |  | 20,168 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial real estate [Member] | Office [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 855 |  | 855 |  | 0 |
Impaired loans, recorded investment, total |  | 855 |  | 855 |  | 0 |
Impaired loans, recorded investment with no related allowance |  | 855 |  | 855 |  | 0 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, average recorded investment |  | 855 |  | 427 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial real estate [Member] | Multifamily [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 275 |  | 275 |  | 301 |
Impaired loans, recorded investment, total |  | 275 |  | 275 |  | 301 |
Impaired loans, recorded investment with no related allowance |  | 275 |  | 275 |  | 301 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, average recorded investment |  | 138 |  | 288 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial real estate [Member] | Industrial [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 0 |  | 0 |  | 0 |
Impaired loans, recorded investment, total |  | 0 |  | 0 |  | 0 |
Impaired loans, recorded investment with no related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, average recorded investment |  | 0 |  | 0 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Commercial real estate [Member] | Other commercial real estate [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 293 |  | 293 |  | 851 |
Impaired loans, recorded investment, total |  | 133 |  | 133 |  | 691 |
Impaired loans, recorded investment with no related allowance |  | 133 |  | 133 |  | 691 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, average recorded investment |  | 139 |  | 412 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Residential mortgage [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 239,379 |  | 239,379 |  | 237,208 |
Impaired loans, recorded investment, total |  | 227,107 |  | 227,107 |  | 225,289 |
Impaired loans, recorded investment with no related allowance |  | 227,107 |  | 227,107 |  | 225,289 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, average recorded investment |  | 224,135 |  | 227,037 |  |  |
Impaired loans, interest income recognized |  | 2,254 |  | 4,457 |  |  |
Residential mortgage [Member] | Permanent mortgage [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 26,434 |  | 26,434 |  | 28,716 |
Impaired loans, recorded investment, total |  | 21,803 |  | 21,803 |  | 23,951 |
Impaired loans, recorded investment with no related allowance |  | 21,803 |  | 21,803 |  | 23,951 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, average recorded investment |  | 22,370 |  | 22,877 |  |  |
Impaired loans, interest income recognized |  | 316 |  | 614 |  |  |
Residential mortgage [Member] | Permanent mortgages guaranteed by US government agencies [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 201,217 | [2] | 201,217 | [2] | 196,296 | [3]
Impaired loans, recorded investment, total |  | 195,373 | [2] | 195,373 | [2] | 190,866 | [3]
Impaired loans, recorded investment with no related allowance |  | 195,373 | [2] | 195,373 | [2] | 190,866 | [3]
Impaired loans, recorded investment with related allowance |  | 0 | [2] | 0 | [2] | 0 | [3]
Impaired loans, related allowance |  | 0 | [2] | 0 | [2] | 0 | [3]
Impaired loans, average recorded investment | [2] | 191,537 |  | 193,958 |  |  |
Impaired loans, interest income recognized | [2] | 1,938 |  | 3,843 |  |  |
Residential mortgage [Member] | Home equity [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 11,728 |  | 11,728 |  | 12,196 |
Impaired loans, recorded investment, total |  | 9,931 |  | 9,931 |  | 10,472 |
Impaired loans, recorded investment with no related allowance |  | 9,931 |  | 9,931 |  | 10,472 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, average recorded investment |  | 10,228 |  | 10,202 |  |  |
Impaired loans, interest income recognized |  | 0 |  | 0 |  |  |
Personal [Member] |  |  |  |  |  |  |
Impaired loans [Abstract] |  |  |  |  |  |  |
Impaired loans, unpaid principal balance |  | 289 |  | 289 |  | 278 |
Impaired loans, recorded investment, total |  | 237 |  | 237 |  | 230 |
Impaired loans, recorded investment with no related allowance |  | 237 |  | 237 |  | 230 |
Impaired loans, recorded investment with related allowance |  | 0 |  | 0 |  | 0 |
Impaired loans, related allowance |  | 0 |  | 0 |  | $ 0 |
Impaired loans, average recorded investment |  | 269 |  | 234 |  |  |
Impaired loans, interest income recognized |  | $ 0 |  | $ 0 |  |  |
[1] | Impaired manufacturing sector loans included $4.7 million of loans from an affiliated entity, with no allowance as the fair value of the collateral exceeded the outstanding principal balance at June 30, 2019.
[2] | All permanent mortgage loans guaranteed by U.S. government agencies are considered impaired as we do not expect full collection of contractual principal and interest. At June 30, 2019, the majority were accruing based on the guarantee by U.S. government agencies.
[3] | All permanent mortgage loans guaranteed by U.S. government agencies are considered impaired as we do not expect full collection of contractual principal and interest. At December 31, 2018, the majority were accruing based on the guarantee by U.S. government agencies.

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