Parent Company Only Financial Statements Parent Company Only Financial Statements, Condensed Income Statements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Income Statements, Captions [Line Items]
Other revenue	$ 51,029	$ 49,883	$ 47,537
Interest expense	81,889	63,474	67,045
Charitable contributions to BOKF Foundation	2,000	796	4,267
Professional fees and services	56,783	40,123	44,440
Other operating expense	1,017,590	896,191	847,522
Federal and state income taxes	106,377	139,384	144,151
Net income attributable to BOK Financial Corp. shareholders	232,668	288,565	292,435
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Dividends, interest and fees received from bank subsidiaries	15,237	150,308	75,412
Dividends, interest and fees received from non-bank subsidiaries	25,923	0	0
Other revenue	1,612	1,279	1,572
Total revenue	42,772	151,587	76,984
Interest expense	4,182	131	293
Charitable contributions to BOKF Foundation	0	0	2,420
Professional fees and services	395	378	600
Other operating expense	1,583	1,864	1,556
Total expense	6,160	2,373	4,869
Income before taxes and equity in undistributed income of subsidiaries	36,612	149,214	72,115
Federal and state income taxes	(1,920)	(375)	(1,702)
Income before equity in undistributed income of subsidiaries	38,532	149,589	73,817
Equity in undistributed income of bank subsidiaries	216,120	134,045	214,435
Equity in undistributed income of non-bank subsidiaries	(21,984)	4,931	4,183
Net income attributable to BOK Financial Corp. shareholders	$ 232,668	$ 288,565	$ 292,435