XML 74 R64.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Fair Value Measurements, Financial Instruments (Details) - USD ($) $ in Thousands | Sep. 30, 2018 | Jun. 30, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Dec. 31, 2016
--- | --- | --- | --- | --- | --- | ---
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | $ 1,613,400 |  | $ 462,676 | $ 614,117 |  |
Investment securities | 374,039 |  | 461,793 | 466,562 |  |
Available for sale securities | 8,072,014 |  | 8,321,578 | 8,383,199 |  |
Fair value option securities | 452,150 |  | 755,054 | 819,531 |  |
Residential mortgage loans held for sale | 175,866 |  | 221,378 | 275,643 |  |
Loans | 18,349,459 |  | 17,153,424 | 17,206,834 |  |
Allowance for loan losses | (210,569) | $ (215,142) | (230,682) | (247,703) | $ (250,061) | $ (246,159)
Loans, net of allowance | 18,138,890 |  | 16,922,742 | 16,959,131 |  |
Mortgage servicing rights | 284,673 | 278,719 | 252,867 | 245,858 | 245,239 | 247,073
Derviative contracts, net of cash collateral, Assets, Fair value | 349,481 |  | 220,502 | 352,559 |  |
Time deposits | 2,075,846 |  | 2,098,416 | 2,172,289 |  |
Subordinated debentures | 144,707 |  | 144,677 | 144,668 |  |
Derivative contracts, net of cash collateral, Liabilities, Fair Value | 252,387 |  | 171,963 | 336,327 |  |
Commercial [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 11,576,101 |  | 10,733,975 | 10,795,934 |  |
Allowance for loan losses | (104,098) | (113,722) | (124,269) | (136,801) | (137,742) | (140,213)
Commercial real estate [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 3,804,675 |  | 3,479,987 | 3,518,142 |  |
Allowance for loan losses | (60,189) | (58,758) | (56,621) | (56,405) | (58,580) | (50,749)
Residential mortgage [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 1,971,742 |  | 1,973,686 | 1,945,750 |  |
Allowance for loan losses | (18,683) | (18,544) | (18,451) | (18,393) | (18,259) | (18,224)
Personal [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 996,941 |  | 965,776 | 947,008 |  |
Allowance for loan losses | (8,709) | $ (8,646) | (9,124) | (8,026) | $ (8,106) | $ (8,773)
U.S. government agency debentures [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 80,692 |  | 21,196 | 30,162 |  |
U.S. government agency residential mortgage-backed securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 1,378,450 |  | 392,673 | 516,760 |  |
Investment securities | 13,234 |  | 15,891 | 16,926 |  |
Available for sale securities | 5,132,352 |  | 5,309,152 | 5,326,384 |  |
Fair value option securities | 452,150 |  | 755,054 | 819,531 |  |
Municipal and other tax-exempt securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 41,345 |  | 13,559 | 56,148 |  |
Investment securities | 157,723 |  | 228,186 | 246,000 |  |
Available for sale securities | 4,349 |  | 27,080 | 28,368 |  |
U.S. Treasury [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 490 |  | 1,000 | 999 |  |
Privately issued residential mortgage-backed securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 74,685 |  | 93,221 | 99,994 |  |
Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 2,834,691 |  | 2,834,961 | 2,889,346 |  |
Other debt securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 40,604 |  | 11,363 | 11,047 |  |
Investment securities | 203,082 |  | 217,716 | 203,636 |  |
Available for sale securities | 25,447 |  | 25,481 | 4,153 |  |
Perpetual preferred stock [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities |  |  | 15,767 | 16,245 |  |
Equity securities and mutual funds [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities |  |  | 14,916 | 17,710 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Cash and due from banks | 815,458 |  | 602,510 | 547,203 |  |
Interest-bearing cash and cash equivalents | 430,789 |  | 1,714,544 | 1,926,779 |  |
Trading securities | 1,613,400 |  | 462,676 | 614,117 |  |
Investment securities | 374,039 |  | 461,793 | 466,562 |  |
Available for sale securities | 8,072,014 |  | 8,321,578 | 8,383,199 |  |
Residential mortgage loans held for sale | 175,866 |  | 221,378 | 275,643 |  |
Loans | 18,349,459 |  | 17,153,424 | 17,206,834 |  |
Allowance for loan losses | (210,569) |  | (230,682) | (247,703) |  |
Loans, net of allowance | 18,138,890 |  | 16,922,742 | 16,959,131 |  |
Mortgage servicing rights | 284,673 |  | 252,867 | 245,858 |  |
Derviative contracts, net of cash collateral, Assets, Fair value | 349,481 |  | 220,502 | 352,559 |  |
Deposits with no stated maturity | 19,556,443 |  | 19,962,889 | 19,675,790 |  |
Time deposits | 2,075,846 |  | 2,098,416 | 2,172,289 |  |
Other borrowed funds | 6,816,224 |  | 5,709,861 | 6,631,820 |  |
Subordinated debentures | 144,707 |  | 144,677 | 144,668 |  |
Derivative contracts, net of cash collateral, Liabilities, Fair Value | 252,387 |  | 171,963 | 336,327 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 11,576,101 |  | 10,733,975 | 10,795,934 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial real estate [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 3,804,675 |  | 3,479,987 | 3,518,142 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Residential mortgage [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 1,971,742 |  | 1,973,686 | 1,945,750 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Personal [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 996,941 |  | 965,776 | 947,008 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. government agency debentures [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 80,692 |  | 21,196 | 30,162 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 1,378,450 |  | 392,673 | 516,760 |  |
Investment securities | 13,234 |  | 15,891 | 16,926 |  |
Available for sale securities | 5,132,352 |  | 5,309,152 | 5,326,384 |  |
Fair value option securities | 452,150 |  | 755,054 | 819,531 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 41,345 |  | 13,559 | 56,148 |  |
Investment securities | 157,723 |  | 228,186 | 246,000 |  |
Available for sale securities | 4,349 |  | 27,080 | 28,368 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Asset-backed securities |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 72,309 |  | 23,885 |  |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other trading securities |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 40,604 |  | 11,363 | 11,047 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. Treasury [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 490 |  | 1,000 | 999 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 74,685 |  | 93,221 | 99,994 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 2,834,691 |  | 2,834,961 | 2,889,346 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other debt securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Investment securities | 203,082 |  | 217,716 | 203,636 |  |
Available for sale securities | 25,447 |  | 25,481 | 4,153 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Perpetual preferred stock [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities |  |  | 15,767 | 16,245 |  |
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Equity securities and mutual funds [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities |  |  | 14,916 | 17,710 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Cash and due from banks | 815,458 |  | 602,510 | 547,203 |  |
Interest-bearing cash and cash equivalents | 430,789 |  | 1,714,544 | 1,926,779 |  |
Trading securities | 1,613,400 |  | 462,676 | 614,117 |  |
Investment securities | 382,893 |  | 480,035 | 489,895 |  |
Available for sale securities | 8,072,014 |  | 8,321,578 | 8,383,199 |  |
Residential mortgage loans held for sale | 175,866 |  | 221,378 | 275,643 |  |
Loans | 18,111,340 |  | 16,887,787 | 16,939,180 |  |
Allowance for loan losses | 0 |  | 0 | 0 |  |
Loans, net of allowance | 18,111,340 |  | 16,887,787 | 16,939,180 |  |
Mortgage servicing rights | 284,673 |  | 252,867 | 245,858 |  |
Derviative contracts, net of cash collateral, Assets, Fair value | 349,481 |  | 220,502 | 352,559 |  |
Deposits with no stated maturity | 19,556,443 |  | 19,962,889 | 19,675,790 |  |
Time deposits | 2,023,244 |  | 2,064,558 | 2,138,367 |  |
Other borrowed funds | 6,530,396 |  | 5,703,121 | 6,609,642 |  |
Subordinated debentures | 144,186 |  | 148,207 | 146,693 |  |
Derivative contracts, net of cash collateral, Liabilities, Fair Value | 252,387 |  | 171,963 | 336,327 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 11,431,818 |  | 10,524,627 | 10,574,720 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 3,738,494 |  | 3,428,733 | 3,467,009 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 1,937,171 |  | 1,977,721 | 1,958,632 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 1,003,857 |  | 956,706 | 938,819 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 80,692 |  | 21,196 | 30,162 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 1,378,450 |  | 392,673 | 516,760 |  |
Investment securities | 13,201 |  | 16,242 | 17,458 |  |
Available for sale securities | 5,132,352 |  | 5,309,152 | 5,326,384 |  |
Fair value option securities | 452,150 |  | 755,054 | 819,531 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 41,345 |  | 13,559 | 56,148 |  |
Investment securities | 158,230 |  | 230,349 | 249,250 |  |
Available for sale securities | 4,349 |  | 27,080 | 28,368 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed securities |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 72,309 |  | 23,885 |  |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 40,604 |  | 11,363 | 11,047 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 490 |  | 1,000 | 999 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 74,685 |  | 93,221 | 99,994 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 2,834,691 |  | 2,834,961 | 2,889,346 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Investment securities | 211,462 |  | 233,444 | 223,187 |  |
Available for sale securities | 25,447 |  | 25,481 | 4,153 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | Perpetual preferred stock [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities |  |  | 15,767 | 16,245 |  |
Estimate of Fair Value, Fair Value Disclosure [Member] | Equity securities and mutual funds [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities |  |  | 14,916 | 17,710 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Cash and due from banks | 815,458 |  | 602,510 | 547,203 |  |
Interest-bearing cash and cash equivalents | 430,789 |  | 1,714,544 | 1,926,779 |  |
Trading securities | 0 |  | 0 | 0 |  |
Investment securities | 0 |  | 0 | 0 |  |
Available for sale securities | 490 |  | 1,000 | 3,577 |  |
Residential mortgage loans held for sale | 0 |  | 0 | 0 |  |
Loans | 0 |  | 0 | 0 |  |
Allowance for loan losses | 0 |  | 0 | 0 |  |
Loans, net of allowance | 0 |  | 0 | 0 |  |
Mortgage servicing rights | 0 |  | 0 | 0 |  |
Derviative contracts, net of cash collateral, Assets, Fair value | 26,196 |  | 8,179 | 8,498 |  |
Deposits with no stated maturity | 0 |  | 0 | 0 |  |
Time deposits | 0 |  | 0 | 0 |  |
Other borrowed funds | 0 |  | 0 | 0 |  |
Subordinated debentures | 0 |  | 0 | 0 |  |
Derivative contracts, net of cash collateral, Liabilities, Fair Value | 17,872 |  | 0 | 6,903 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 0 |  | 0 | 0 |  |
Investment securities | 0 |  | 0 | 0 |  |
Available for sale securities | 0 |  | 0 | 0 |  |
Fair value option securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 0 |  | 0 | 0 |  |
Investment securities | 0 |  | 0 | 0 |  |
Available for sale securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed securities |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 0 |  | 0 |  |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 490 |  | 1,000 | 999 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Investment securities | 0 |  | 0 | 0 |  |
Available for sale securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Perpetual preferred stock [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities |  |  | 0 | 0 |  |
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Equity securities and mutual funds [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities |  |  | 0 | 2,578 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Cash and due from banks | 0 |  | 0 | 0 |  |
Interest-bearing cash and cash equivalents | 0 |  | 0 | 0 |  |
Trading securities | 1,613,400 |  | 462,676 | 614,117 |  |
Investment securities | 382,893 |  | 480,035 | 489,895 |  |
Available for sale securities | 8,071,052 |  | 8,315,304 | 8,370,684 |  |
Residential mortgage loans held for sale | 159,028 |  | 209,079 | 263,543 |  |
Loans | 0 |  | 0 | 0 |  |
Allowance for loan losses | 0 |  | 0 | 0 |  |
Loans, net of allowance | 0 |  | 0 | 0 |  |
Mortgage servicing rights | 0 |  | 0 | 0 |  |
Derviative contracts, net of cash collateral, Assets, Fair value | 323,285 |  | 212,323 | 344,061 |  |
Deposits with no stated maturity | 0 |  | 0 | 0 |  |
Time deposits | 0 |  | 0 | 0 |  |
Other borrowed funds | 0 |  | 0 | 0 |  |
Subordinated debentures | 144,186 |  | 148,207 | 146,693 |  |
Derivative contracts, net of cash collateral, Liabilities, Fair Value | 234,515 |  | 171,963 | 329,424 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 80,692 |  | 21,196 | 30,162 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 1,378,450 |  | 392,673 | 516,760 |  |
Investment securities | 13,201 |  | 16,242 | 17,458 |  |
Available for sale securities | 5,132,352 |  | 5,309,152 | 5,326,384 |  |
Fair value option securities | 452,150 |  | 755,054 | 819,531 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 41,345 |  | 13,559 | 56,148 |  |
Investment securities | 158,230 |  | 230,349 | 249,250 |  |
Available for sale securities | 4,349 |  | 22,278 | 23,583 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed securities |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 72,309 |  | 23,885 |  |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 40,604 |  | 11,363 | 11,047 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 74,685 |  | 93,221 | 99,994 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 2,834,691 |  | 2,834,961 | 2,889,346 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Investment securities | 211,462 |  | 233,444 | 223,187 |  |
Available for sale securities | 24,975 |  | 25,009 | 0 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Perpetual preferred stock [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities |  |  | 15,767 | 16,245 |  |
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Equity securities and mutual funds [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities |  |  | 14,916 | 15,132 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Cash and due from banks | 0 |  | 0 | 0 |  |
Interest-bearing cash and cash equivalents | 0 |  | 0 | 0 |  |
Trading securities | 0 |  | 0 | 0 |  |
Investment securities | 0 |  | 0 | 0 |  |
Available for sale securities | 472 |  | 5,274 | 8,938 |  |
Residential mortgage loans held for sale | 16,838 |  | 12,299 | 12,100 |  |
Loans | 18,111,340 |  | 16,887,787 | 16,939,180 |  |
Allowance for loan losses | 0 |  | 0 | 0 |  |
Loans, net of allowance | 18,111,340 |  | 16,887,787 | 16,939,180 |  |
Mortgage servicing rights | 284,673 |  | 252,867 | 245,858 |  |
Derviative contracts, net of cash collateral, Assets, Fair value | 0 |  | 0 | 0 |  |
Deposits with no stated maturity | 19,556,443 |  | 19,962,889 | 19,675,790 |  |
Time deposits | 2,023,244 |  | 2,064,558 | 2,138,367 |  |
Other borrowed funds | 6,530,396 |  | 5,703,121 | 6,609,642 |  |
Subordinated debentures | 0 |  | 0 | 0 |  |
Derivative contracts, net of cash collateral, Liabilities, Fair Value | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 11,431,818 |  | 10,524,627 | 10,574,720 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 3,738,494 |  | 3,428,733 | 3,467,009 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 1,937,171 |  | 1,977,721 | 1,958,632 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Loans | 1,003,857 |  | 956,706 | 938,819 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 0 |  | 0 | 0 |  |
Investment securities | 0 |  | 0 | 0 |  |
Available for sale securities | 0 |  | 0 | 0 |  |
Fair value option securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 0 |  | 0 | 0 |  |
Investment securities | 0 |  | 0 | 0 |  |
Available for sale securities |  |  | 4,802 | 4,785 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed securities |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 0 |  | 0 |  |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Trading securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities | 0 |  | 0 | 0 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Investment securities | 0 |  | 0 | 0 |  |
Available for sale securities | $ 472 |  | 472 | 4,153 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Perpetual preferred stock [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities |  |  | 0 | 0 |  |
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Equity securities and mutual funds [Member] |  |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |  |
Available for sale securities |  |  | $ 0 | $ 0 |  |

X
- Definition This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. May be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. May be used in both the balance sheet and disclosure in the same submission. Represents time deposits with no stated maturity as presented on the statement of financial position. + References No definition available. + Details
Name: | bokf_DepositsNoStatedMaturityFairValueDisclosure
Namespace Prefix: | bokf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value option securities represent securities the Company has elected to carry at fair value and separately identified on the balance sheet with changes in fair value recognized in earnings as they occur. Certain residential mortgage-backed securities issued by US government agencies are held as an economic hedge of changes in the fair value of mortgage servicing rights and related derivative contracts. In addition, other securities may be held to manage interest rate risk or for deferred compensation purposes. Securities held for interest rate risk management may be economically hedged by derivative contracts not designated as hedging instruments effectively modify these fixed rate securities into variable rate securities. + References No definition available. + Details
Name: | bokf_FairValueOptionSecurities
Namespace Prefix: | bokf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents money market or interest-bearing cash accounts held in other financial institutions (including the Federal Reserve); federal funds sold to other depository institutions, securities brokers or securities dealers and securities purchased under agreements to resell. + References No definition available. + Details
Name: | bokf_Interestbearingcashandcashequivalents
Namespace Prefix: | bokf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References No definition available. + Details
Name: | us-gaap_CashAndCashEquivalentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
Name: | us-gaap_DerivativeAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313 + Details
Name: | us-gaap_DerivativeLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563 + Details
Name: | us-gaap_HeldToMaturitySecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for 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 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.7(d)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b)(1)(ii) -URI http://asc.fasb.org/extlink&oid=82894903&loc=d3e15032-111544 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L.1) -URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707 + Details
Name: | us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- 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=82891408&loc=d3e4428-111522 + Details
Name: | us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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
Name: | us-gaap_LoansAndLeasesReceivableNetReportedAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, after allowance for bad debt, of mortgage loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities. + 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 + Details
Name: | us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroupMortgage
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of other liabilities. + References No definition available. + Details
Name: | us-gaap_OtherLiabilitiesFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122625-111746 + Details
Name: | us-gaap_ServicingAssetAtFairValueAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 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(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_SubordinatedDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of time deposit liabilities, including certificates of deposit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 405 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=50488274&loc=d3e64164-112818 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 210.9-03.12) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_TimeDeposits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562 + Details
Name: | us-gaap_TradingSecuritiesDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CommercialMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_PreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=bokf_EquitySecuritiesAndMutualFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=bokf_OtherTradingSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |