Consolidated Statements of Patronage Capital and Membership Fees (Unaudited) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Increase (Decrease) in Members' Capital
Net margin	$ 27,127			$ 32,097			$ 69,951	$ 72,244
Patronage Capital and Membership Fees
Increase (Decrease) in Members' Capital
Beginning balance	1,234,951	$ 1,216,537	$ 1,192,127	1,170,570	$ 1,152,403	$ 1,130,423	1,192,127	1,130,423
Net margin	27,127	18,414	24,410	32,097	18,167	21,980
Ending balance	$ 1,262,078	$ 1,234,951	$ 1,216,537	$ 1,202,667	$ 1,170,570	$ 1,152,403	$ 1,262,078	$ 1,202,667