Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands |
12 Months Ended |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
Common stock, authorized (in shares) |
|
2,500,000,000
|
2,500,000,000
|
|
Common stock, par value (in dollars per share) |
|
$ 0.00006
|
$ 0.00006
|
|
Dividends declared and paid |
|
$ 115,281
|
$ 111,026
|
$ 104,722
|
Accumulated Other Comprehensive Income [Roll Forward] |
|
|
|
|
Beginning balance |
|
56,673
|
(25,623)
|
149,920
|
Net change in unrealized gain (loss) |
|
(46,803)
|
136,775
|
(275,945)
|
Reclassification adjustments included in earnings: [Abstract] |
|
|
|
|
Interest revenue, Investment securities, Taxable securities |
|
(503)
|
(1,216)
|
(3,210)
|
Interest expense, Subordinated debentures |
|
121
|
296
|
262
|
Net impairment losses recognized in earnings |
|
1,819
|
373
|
2,308
|
Gain on available for sale securities, net |
|
(12,058)
|
(1,539)
|
(10,720)
|
Other comprehensive income (loss), before income taxes |
|
(57,424)
|
134,689
|
(287,305)
|
Federal and state income taxes |
[1] |
(22,338)
|
52,393
|
(111,762)
|
Other comprehensive income (loss), net of income taxes |
|
(35,086)
|
82,296
|
(175,543)
|
Ending balance |
|
$ 21,587
|
$ 56,673
|
(25,623)
|
Total Capital (to Risk Weighted Assets) [Abstract] |
|
|
|
|
Total Capital Ratio Required to be Well Capitalized |
|
10.00%
|
10.00%
|
|
Minimum Capital Requirement, Total Capital to Risk Weighted Assets |
[2] |
4.50%
|
|
|
Capital Conservation Buffer, Total Capital to Risk Weighted Assets |
[3] |
2.50%
|
|
|
Minimum Capital Requirement Including Capital Conservation Buffer, Total Capital to Risk Weighted Assets |
|
7.00%
|
|
|
Total Capital |
|
$ 3,116,144
|
$ 3,120,223
|
|
Total Capital to Risk Weighted Assets |
|
13.30%
|
14.66%
|
|
Common Equity Tier 1 (to Risk Weighted Assets) [Abstract] |
|
|
|
|
Common Equity Tier 1 Capital Ratio Required to be Well Capitalized |
|
6.50%
|
|
|
Minimum Capital Requirement, Common equity Tier 1 Capital to Risk Weighted Assets |
[2] |
6.00%
|
|
|
Capital Conservation Buffer, Common equity Tier 1 to Risk Weighted Assets |
[3] |
2.50%
|
|
|
Minimum Capital Requirement Including Capital Conservation Buffer, Common equity Tier 1 to Risk Weighted Assets |
|
8.50%
|
|
|
Common Equity Tier 1 Capital |
|
$ 2,842,193
|
|
|
Common Equity Tier One Risk Based Capital to Risk Weighted Assets |
|
12.13%
|
|
|
Tier I Capital (to Risk Weighted Assets) [Abstract] |
|
|
|
|
Tier I Capital Ratio Required to be Well Capitalized |
|
8.00%
|
6.00%
|
|
Minimum Capital Requirement, Tier 1 Capital to Risk Weighted Assets |
[2] |
8.00%
|
|
|
Capital Conservation Buffer, Tier 1 Capital to Risk Weighted Assets |
[3] |
2.50%
|
|
|
Minimum Capital Requirement Including Capital Conservation Buffer, Tier One to Risk Weighted Assets |
|
10.50%
|
|
|
Tier 1 Capital |
|
$ 2,842,193
|
$ 2,838,129
|
|
Tier I Capital to Risk Weighted Assets |
|
12.13%
|
13.33%
|
|
Tier I Capital (to Average Assets) [Abstract] |
|
|
|
|
Leverage Ratio Required to be Well Capitalized |
|
5.00%
|
5.00%
|
|
Minimum Capital Requirement, Tier 1 Capital to Average Assets |
[2] |
4.00%
|
|
|
Minimum Capital Requirements Including Capital Conservation Buffer, Tier One Capital to Average Assets |
|
4.00%
|
|
|
Tier I Capital to Average Assets |
|
9.25%
|
9.96%
|
|
Accumulated Unrealized Gain (Loss) on Available for Sale Securities [Member] |
|
|
|
|
Accumulated Other Comprehensive Income [Roll Forward] |
|
|
|
|
Beginning balance |
|
$ 59,239
|
$ (23,175)
|
155,553
|
Net change in unrealized gain (loss) |
|
(48,607)
|
136,050
|
(284,104)
|
Reclassification adjustments included in earnings: [Abstract] |
|
|
|
|
Interest revenue, Investment securities, Taxable securities |
|
0
|
0
|
0
|
Interest expense, Subordinated debentures |
|
0
|
0
|
0
|
Net impairment losses recognized in earnings |
|
1,819
|
373
|
2,308
|
Gain on available for sale securities, net |
|
(12,058)
|
(1,539)
|
(10,720)
|
Other comprehensive income (loss), before income taxes |
|
(58,846)
|
134,884
|
(292,516)
|
Federal and state income taxes |
[1] |
(22,891)
|
52,470
|
(113,788)
|
Other comprehensive income (loss), net of income taxes |
|
(35,955)
|
82,414
|
(178,728)
|
Ending balance |
|
23,284
|
59,239
|
(23,175)
|
Accumulated Unrealized Gain on Investment Securities Transferred from AFS [Member] |
|
|
|
|
Accumulated Other Comprehensive Income [Roll Forward] |
|
|
|
|
Beginning balance |
|
376
|
1,118
|
3,078
|
Net change in unrealized gain (loss) |
|
0
|
0
|
0
|
Reclassification adjustments included in earnings: [Abstract] |
|
|
|
|
Interest revenue, Investment securities, Taxable securities |
|
(503)
|
(1,216)
|
(3,210)
|
Interest expense, Subordinated debentures |
|
0
|
0
|
0
|
Net impairment losses recognized in earnings |
|
0
|
0
|
0
|
Gain on available for sale securities, net |
|
0
|
0
|
0
|
Other comprehensive income (loss), before income taxes |
|
(503)
|
(1,216)
|
(3,210)
|
Federal and state income taxes |
[1] |
(195)
|
(474)
|
(1,250)
|
Other comprehensive income (loss), net of income taxes |
|
(308)
|
(742)
|
(1,960)
|
Ending balance |
|
68
|
376
|
1,118
|
Accumulated Unrealized Gain (Loss) on Employee Benefit Plans [Member] |
|
|
|
|
Accumulated Other Comprehensive Income [Roll Forward] |
|
|
|
|
Beginning balance |
|
(2,868)
|
(3,311)
|
(8,296)
|
Net change in unrealized gain (loss) |
|
1,804
|
725
|
8,159
|
Reclassification adjustments included in earnings: [Abstract] |
|
|
|
|
Interest revenue, Investment securities, Taxable securities |
|
0
|
0
|
0
|
Interest expense, Subordinated debentures |
|
0
|
0
|
0
|
Net impairment losses recognized in earnings |
|
0
|
0
|
0
|
Gain on available for sale securities, net |
|
0
|
0
|
0
|
Other comprehensive income (loss), before income taxes |
|
1,804
|
725
|
8,159
|
Federal and state income taxes |
[1] |
701
|
282
|
3,174
|
Other comprehensive income (loss), net of income taxes |
|
1,103
|
443
|
4,985
|
Ending balance |
|
(1,765)
|
(2,868)
|
(3,311)
|
Accumulated Loss on Effective Cash Flow Hedges [Member] |
|
|
|
|
Accumulated Other Comprehensive Income [Roll Forward] |
|
|
|
|
Beginning balance |
|
(74)
|
(255)
|
(415)
|
Net change in unrealized gain (loss) |
|
0
|
0
|
0
|
Reclassification adjustments included in earnings: [Abstract] |
|
|
|
|
Interest revenue, Investment securities, Taxable securities |
|
0
|
0
|
0
|
Interest expense, Subordinated debentures |
|
121
|
296
|
262
|
Net impairment losses recognized in earnings |
|
0
|
0
|
0
|
Gain on available for sale securities, net |
|
0
|
0
|
0
|
Other comprehensive income (loss), before income taxes |
|
121
|
296
|
262
|
Federal and state income taxes |
[1] |
47
|
115
|
102
|
Other comprehensive income (loss), net of income taxes |
|
74
|
181
|
160
|
Ending balance |
|
0
|
(74)
|
(255)
|
BOKF, NA [Member] |
|
|
|
|
Allowed dividends without regulatory approval |
|
100,000
|
|
|
Dividends declared and paid |
|
$ 150,000
|
75,000
|
$ 225,000
|
Maximum percentage of unimpaired capital on loan commitments and equity investments to a single affiliate (in hundredths) |
|
10.00%
|
|
|
Maximum percentage of unimpaired capital on loan commitments and equity investments to all affiliates (in hundredths) |
|
20.00%
|
|
|
Maximum loan commitments and equity investments to a single affiliate |
|
$ 266,000
|
|
|
Maximum loan commitments and equity investments to all affiliates |
|
532,000
|
|
|
Largest loan commitment and equity investment to a single affiliate |
|
220,000
|
|
|
Aggregate loan commitment and equity investment to all affiliates |
|
330,000
|
330,000
|
|
Largest amount outstanding to a single affiliate |
|
218,000
|
|
|
Outstanding amounts to all affiliates |
|
$ 244,000
|
18,000
|
|
Total Capital (to Risk Weighted Assets) [Abstract] |
|
|
|
|
Minimum Capital Requirement, Total Capital to Risk Weighted Assets |
[2] |
4.50%
|
|
|
Minimum Capital Requirement Including Capital Conservation Buffer, Total Capital to Risk Weighted Assets |
|
4.50%
|
|
|
Total Capital |
|
$ 2,657,935
|
$ 2,449,078
|
|
Total Capital to Risk Weighted Assets |
|
11.43%
|
11.56%
|
|
Common Equity Tier 1 (to Risk Weighted Assets) [Abstract] |
|
|
|
|
Minimum Capital Requirement, Common equity Tier 1 Capital to Risk Weighted Assets |
[2] |
6.00%
|
|
|
Minimum Capital Requirement Including Capital Conservation Buffer, Common equity Tier 1 to Risk Weighted Assets |
|
6.00%
|
|
|
Common Equity Tier 1 Capital |
|
$ 2,385,323
|
|
|
Common Equity Tier One Risk Based Capital to Risk Weighted Assets |
|
10.26%
|
|
|
Tier I Capital (to Risk Weighted Assets) [Abstract] |
|
|
|
|
Minimum Capital Requirement, Tier 1 Capital to Risk Weighted Assets |
[2] |
8.00%
|
|
|
Minimum Capital Requirement Including Capital Conservation Buffer, Tier One to Risk Weighted Assets |
|
8.00%
|
|
|
Tier 1 Capital |
|
$ 2,385,323
|
$ 2,168,161
|
|
Tier I Capital to Risk Weighted Assets |
|
10.26%
|
10.24%
|
|
Tier I Capital (to Average Assets) [Abstract] |
|
|
|
|
Minimum Capital Requirement, Tier 1 Capital to Average Assets |
[2] |
4.00%
|
|
|
Minimum Capital Requirements Including Capital Conservation Buffer, Tier One Capital to Average Assets |
|
4.00%
|
|
|
Tier I Capital to Average Assets |
|
7.81%
|
7.65%
|
|
Perpetual stock [Member] |
|
|
|
|
Preferred stock, authorized (in shares) |
|
1,000,000,000
|
|
|
Preferred stock at par value (in dollars per share) |
|
$ 0.00005
|
|
|
Preferred stock conversion rate |
|
one share of Common Stock for each 36 shares of Series A Preferred Stock at the option of the holder
|
|
|
Preferred stock, Rate of annual cumulative dividends (in hundredths) |
|
10.00%
|
|
|
Preferred stock, Liquidation preference per share |
|
$ 0.06
|
|
|
Preferred stock, Aggregate liquidation preference |
|
$ 15,000
|
|
|
Preferred Stock, Shares Outstanding |
|
0
|
0
|
0
|
Common Stock [Member] |
|
|
|
|
Common stock, authorized (in shares) |
|
2,500,000,000
|
|
|
Common stock, par value (in dollars per share) |
|
$ 0.00006
|
|
|
Common stock, number of vote per share |
|
$ 1
|
|
|
|
|