Transactions With Stockholders (Related Party Transactions, by Balance Sheet Grouping) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Related Party Transaction [Line Items]
Outstanding Advances	$ 46,219,747		$ 46,219,747		$ 45,444,769
Outstanding Deposits	817,072		817,072		752,200
Ten Percent Owner [Member]
Related Party Transaction [Line Items]
Regulatory Capital Stock, Total Par Value	$ 910,757		$ 910,757		$ 826,330
Regulatory Capital Stock, Percent Of Total	33.20%		33.20%		31.70%
Outstanding Advances	$ 17,340,000		$ 17,340,000		$ 17,260,000
Outstanding Advances, Percent of Total	37.30%		37.30%		37.80%
Outstanding Deposits	$ 63,844		$ 63,844		$ 26,076
Outstanding Deposits, Percent of Total	7.80%		7.80%		3.50%
Ten Percent Owner [Member] | Total Class A Stock [Member]
Related Party Transaction [Line Items]
Regulatory Capital Stock, Total Par Value	$ 75,499		$ 75,499		$ 35,973
Regulatory Capital Stock, Percent Of Total	23.60%		23.60%		12.90%
Ten Percent Owner [Member] | Total Class B Stock [Member]
Related Party Transaction [Line Items]
Regulatory Capital Stock, Total Par Value	$ 835,258		$ 835,258		$ 790,357
Regulatory Capital Stock, Percent Of Total	34.50%		34.50%		33.90%
MidFirst Bank [Member]
Related Party Transaction [Line Items]
Regulatory Capital Stock, Total Par Value	$ 513,252		$ 513,252		$ 478,818
Regulatory Capital Stock, Percent Of Total	18.70%		18.70%		18.40%
Outstanding Advances	$ 10,840,000		$ 10,840,000		$ 9,585,000
Outstanding Advances, Percent of Total	23.30%		23.30%		21.00%
Outstanding Deposits	$ 5,078		$ 5,078		$ 3,751
Outstanding Deposits, Percent of Total	0.60%		0.60%		0.50%
Loans And Leases Receivable, Acquired or Funded With Related Party During Period	$ 0	$ 0	$ 0	$ 0
MidFirst Bank [Member] | Total Class A Stock [Member]
Related Party Transaction [Line Items]
Regulatory Capital Stock, Total Par Value	$ 3,202		$ 3,202		$ 35,473
Regulatory Capital Stock, Percent Of Total	1.00%		1.00%		12.70%
MidFirst Bank [Member] | Total Class B Stock [Member]
Related Party Transaction [Line Items]
Regulatory Capital Stock, Total Par Value	$ 510,050		$ 510,050		$ 443,345
Regulatory Capital Stock, Percent Of Total	21.10%		21.10%		19.00%
BOKF, N.A. [Member]
Related Party Transaction [Line Items]
Regulatory Capital Stock, Total Par Value	$ 397,505		$ 397,505		$ 347,512
Regulatory Capital Stock, Percent Of Total	14.50%		14.50%		13.30%
Outstanding Advances	$ 6,500,000		$ 6,500,000		$ 7,675,000
Outstanding Advances, Percent of Total	14.00%		14.00%		16.80%
Outstanding Deposits	$ 58,766		$ 58,766		$ 22,325
Outstanding Deposits, Percent of Total	7.20%		7.20%		3.00%
Loans And Leases Receivable, Acquired or Funded With Related Party During Period	$ 12,143		$ 20,941
BOKF, N.A. [Member] | Total Class A Stock [Member]
Related Party Transaction [Line Items]
Regulatory Capital Stock, Total Par Value	$ 72,297		$ 72,297		$ 500
Regulatory Capital Stock, Percent Of Total	22.60%		22.60%		0.20%
BOKF, N.A. [Member] | Total Class B Stock [Member]
Related Party Transaction [Line Items]
Regulatory Capital Stock, Total Par Value	$ 325,208		$ 325,208		$ 347,012
Regulatory Capital Stock, Percent Of Total	13.40%		13.40%		14.90%