Summary Of Significant Accounting Policies - Additional Information (Details) $ in Thousands		12 Months Ended
	Dec. 14, 2021 USD ($)	Dec. 31, 2023 USD ($) Representative Member Product Segment Member_class Cooperative	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Significant Accounting Policies [Line Items]
Consolidated assets		$ 2,232,350	$ 2,204,979
Number of classes of members | Member_class		2
Number of Class A members | Member		11
Number of representatives from each Class A member on the board of directors | Representative		2
Number of representatives from each Class B member on the board of directors | Representative		1
Reimbursement of nuclear fuel costs receivable		$ 2,200	1,900
Interest costs capitalized		$ 1,400	1,300	$ 900
Percentage of income received from members		85.00%
Number of Member Distributions Cooperatives | Cooperative		11
Number of power products for sale | Product		2
Percentage change in energy rate due to revision of energy adjustment rate		2.00%
Percentage of budgeted total interest charges		20.00%
Percentage of actual interest charges		20.00%
Member distribution cooperatives, amount prepaid		$ 40,800	105,800
Member distribution cooperatives, amount extended		18,400	8,900
Deferred energy, asset			83,800
Deferred energy, liability		$ 30,700
Additional equity contribution	$ 8,700
Retirement of patronage capital	$ 8,700			$ 8,740
Payment date of patronage capital	Mar. 25, 2022
Reduction of patronage capital	$ 8,700
Increase in accounts payable-members	$ 8,700
Number of operating segments | Segment		1
Number of reportable segments | Segment		1
Related Party [Member]
Significant Accounting Policies [Line Items]
Accounts receivable-members		$ 108,200	111,800
Long-term Debt [Member]
Significant Accounting Policies [Line Items]
Capitalized costs associated with the issuance of debt		4,400	4,800
Deferred Charges And Other Assets - Other [Member]
Significant Accounting Policies [Line Items]
Capitalized costs associated with the issuance of debt		700	300
Variable Interest Entity Primary Beneficiary [Member]
Significant Accounting Policies [Line Items]
Consolidated assets		$ 6,600	$ 12,700
Maximum [Member]
Significant Accounting Policies [Line Items]
Derivative term		3 years
TEC [Member]
Significant Accounting Policies [Line Items]
Percentage of interest owned in subsidiary by our Class A members		100.00%