Loans and Allowances for Credit Losses Part 2 (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012		Sep. 30, 2013	Sep. 30, 2012		Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Allowance for loan losses [Roll Forward]
Beginning balance				$ 215,507,000	$ 253,481,000		$ 203,124,000		$ 231,669,000
Provision for loan losses	(8,500,000)	7,804,000		(16,189,000)	(682,000)
Loans charged off	(4,708,000)	(8,921,000)		(22,169,000)	(34,138,000)
Recoveries	4,409,000	3,204,000		17,176,000	15,095,000
Ending balance	194,325,000	233,756,000		194,325,000	233,756,000		203,124,000		231,669,000
Allowance for off-balance sheet credit losses [Roll Forward]
Beginning balance				1,915,000	9,261,000		1,604,000		9,747,000
Provision for off-balance sheet credit losses	0	(7,804,000)		(311,000)	(7,318,000)
Ending balance	1,604,000	1,943,000		1,604,000	1,943,000		1,604,000		9,747,000
Total provision for credit losses	(8,500,000)	0		(16,500,000)	(8,000,000)
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	12,237,773,000	11,700,978,000		12,237,773,000	11,700,978,000			12,177,535,000
Individually measured for impairment, recorded investment	112,327,000	131,389,000		112,327,000	131,389,000			133,921,000
Total	12,350,100,000	11,832,367,000		12,350,100,000	11,832,367,000			12,311,456,000
Related allowance [Abstract]
Collectively measured for impairment, related allowance	152,169,000	189,175,000		152,169,000	189,175,000			167,087,000
Individually measured for impairment, related allowance	1,274,000	3,667,000		1,274,000	3,667,000			4,233,000
Total measured for impairment, related allowance	194,325,000	233,756,000		194,325,000	233,756,000		203,124,000		231,669,000
Commercial [Member]
Allowance for loan losses [Roll Forward]
Beginning balance				65,280,000	83,443,000		64,044,000		83,477,000
Provision for loan losses	(1,774,000)	4,000		(3,507,000)	995,000
Loans charged off	(1,354,000)	(812,000)		(6,190,000)	(7,840,000)
Recoveries	864,000	(890,000)	[1]	6,197,000	5,181,000	[1]
Ending balance	61,780,000	81,779,000		61,780,000	81,779,000		64,044,000		83,477,000
Allowance for off-balance sheet credit losses [Roll Forward]
Beginning balance				475,000	7,906,000		402,000		8,224,000
Provision for off-balance sheet credit losses	(228,000)	(7,823,000)		(301,000)	(7,505,000)
Ending balance	174,000	401,000		174,000	401,000		402,000		8,224,000
Total provision for credit losses	(2,002,000)	(7,819,000)		(3,808,000)	(6,510,000)
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	7,551,553,000	7,245,145,000		7,551,553,000	7,245,145,000			7,617,445,000
Individually measured for impairment, recorded investment	19,522,000	21,762,000		19,522,000	21,762,000			24,467,000
Total	7,571,075,000	7,266,907,000		7,571,075,000	7,266,907,000			7,641,912,000
Related allowance [Abstract]
Collectively measured for impairment, related allowance	61,208,000	81,575,000		61,208,000	81,575,000			65,050,000
Individually measured for impairment, related allowance	572,000	204,000		572,000	204,000			230,000
Total measured for impairment, related allowance	61,780,000	81,779,000		61,780,000	81,779,000		64,044,000		83,477,000
Commercial Real Estate [Member]
Allowance for loan losses [Roll Forward]
Beginning balance				54,884,000	67,034,000		49,687,000		55,806,000
Provision for loan losses	(6,279,000)	4,821,000		(10,077,000)	(322,000)
Loans charged off	(419,000)	(2,607,000)		(5,669,000)	(10,548,000)
Recoveries	2,073,000	2,684,000		5,924,000	4,540,000
Ending balance	45,062,000	60,704,000		45,062,000	60,704,000		49,687,000		55,806,000
Allowance for off-balance sheet credit losses [Roll Forward]
Beginning balance				1,353,000	1,250,000		1,178,000		1,425,000
Provision for off-balance sheet credit losses	202,000	18,000		27,000	193,000
Ending balance	1,380,000	1,443,000		1,380,000	1,443,000		1,178,000		1,425,000
Total provision for credit losses	(6,077,000)	4,839,000		(10,050,000)	(129,000)
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	2,296,727,000	2,101,511,000		2,296,727,000	2,101,511,000			2,168,373,000
Individually measured for impairment, recorded investment	52,502,000	75,761,000		52,502,000	75,761,000			60,626,000
Total	2,349,229,000	2,177,272,000		2,349,229,000	2,177,272,000			2,228,999,000
Related allowance [Abstract]
Collectively measured for impairment, related allowance	44,574,000	57,587,000		44,574,000	57,587,000			51,775,000
Individually measured for impairment, related allowance	488,000	3,117,000		488,000	3,117,000			3,109,000
Total measured for impairment, related allowance	45,062,000	60,704,000		45,062,000	60,704,000		49,687,000		55,806,000
Residential Mortgage [Member]
Allowance for loan losses [Roll Forward]
Beginning balance				41,703,000	46,476,000		39,206,000		42,688,000
Provision for loan losses	(136,000)	(370,000)		187,000	528,000
Loans charged off	(961,000)	(1,600,000)		(4,797,000)	(7,447,000)
Recoveries	188,000	298,000		1,204,000	1,459,000
Ending balance	38,297,000	41,016,000		38,297,000	41,016,000		39,206,000		42,688,000
Allowance for off-balance sheet credit losses [Roll Forward]
Beginning balance				78,000	91,000		6,000		80,000
Provision for off-balance sheet credit losses	42,000	(4,000)		(30,000)	(15,000)
Ending balance	48,000	76,000		48,000	76,000		6,000		80,000
Total provision for credit losses	(94,000)	(374,000)		157,000	513,000
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	1,996,086,000	1,987,546,000		1,996,086,000	1,987,546,000			1,998,921,000
Individually measured for impairment, recorded investment	38,679,000	28,757,000		38,679,000	28,757,000			46,119,000
Total	2,034,765,000	2,016,303,000		2,034,765,000	2,016,303,000			2,045,040,000
Related allowance [Abstract]
Collectively measured for impairment, related allowance	38,083,000	40,799,000		38,083,000	40,799,000			40,934,000
Individually measured for impairment, related allowance	214,000	217,000		214,000	217,000			769,000
Total measured for impairment, related allowance	38,297,000	41,016,000		38,297,000	41,016,000		39,206,000		42,688,000
Consumer [Member]
Allowance for loan losses [Roll Forward]
Beginning balance				9,453,000	10,178,000		7,738,000		8,840,000
Provision for loan losses	1,256,000	3,293,000		513,000	3,553,000
Loans charged off	(1,974,000)	(3,902,000)		(5,513,000)	(8,303,000)
Recoveries	1,284,000	1,112,000		3,851,000	3,915,000
Ending balance	8,304,000	9,343,000		8,304,000	9,343,000		7,738,000		8,840,000
Allowance for off-balance sheet credit losses [Roll Forward]
Beginning balance				9,000	14,000		18,000		18,000
Provision for off-balance sheet credit losses	(16,000)	5,000		(7,000)	9,000
Ending balance	2,000	23,000		2,000	23,000		18,000		18,000
Total provision for credit losses	1,240,000	3,298,000		506,000	3,562,000
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	393,407,000	366,776,000		393,407,000	366,776,000			392,796,000
Individually measured for impairment, recorded investment	1,624,000	5,109,000		1,624,000	5,109,000			2,709,000
Total	395,031,000	371,885,000		395,031,000	371,885,000			395,505,000
Related allowance [Abstract]
Collectively measured for impairment, related allowance	8,304,000	9,214,000		8,304,000	9,214,000			9,328,000
Individually measured for impairment, related allowance	0	129,000		0	129,000			125,000
Total measured for impairment, related allowance	8,304,000	9,343,000		8,304,000	9,343,000		7,738,000		8,840,000
Specific Allowance [Member]
Allowance for loan losses [Roll Forward]
Beginning balance								171,320,000
Ending balance	153,443,000	192,842,000		153,443,000	192,842,000			171,320,000
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	12,237,773,000	11,700,978,000		12,237,773,000	11,700,978,000			12,177,535,000
Individually measured for impairment, recorded investment	112,327,000	131,389,000		112,327,000	131,389,000			133,921,000
Total	12,350,100,000	11,832,367,000		12,350,100,000	11,832,367,000			12,311,456,000
Related allowance [Abstract]
Collectively measured for impairment, related allowance	152,169,000	189,175,000		152,169,000	189,175,000			167,087,000
Individually measured for impairment, related allowance	1,274,000	3,667,000		1,274,000	3,667,000			4,233,000
Total measured for impairment, related allowance	153,443,000	192,842,000		153,443,000	192,842,000			171,320,000
Nonspecific Allowance [Member]
Allowance for loan losses [Roll Forward]
Beginning balance				44,187,000	46,350,000		42,449,000		40,858,000
Provision for loan losses	(1,567,000)	56,000		(3,305,000)	(5,436,000)
Loans charged off	0	0		0	0
Recoveries	0	0		0	0
Ending balance	40,882,000	40,914,000		40,882,000	40,914,000		42,449,000		40,858,000
Allowance for off-balance sheet credit losses [Roll Forward]
Beginning balance				0	0		0		0
Provision for off-balance sheet credit losses	0	0		0	0
Ending balance	0	0		0	0		0		0
Total provision for credit losses	(1,567,000)	56,000		(3,305,000)	(5,436,000)
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	0	0		0	0			0
Individually measured for impairment, recorded investment	0	0		0	0			0
Total	0	0		0	0			0
Related allowance [Abstract]
Collectively measured for impairment, related allowance	0	0		0	0			0
Individually measured for impairment, related allowance	0	0		0	0			0
Total measured for impairment, related allowance	$ 40,882,000	$ 40,914,000		$ 40,882,000	$ 40,914,000		$ 42,449,000		$ 40,858,000

[1] Includes $7.1 million of negative recovery related to a refund of a settlement between BOK Financial and the City of Tulsa by the Oklahoma Supreme Court. Excluding this refund, BOK Financial had net charge-offs (recoveries) to average loans of (0.05%) on an annualized basis.