Consolidated Statements of Patronage Capital and Membership Fees (Unaudited) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Increase (Decrease) in Members' Capital
Net margin	$ 18,414		$ 18,167		$ 42,824	$ 40,147
Patronage Capital and Membership Fees
Increase (Decrease) in Members' Capital
Beginning balance	1,216,537	$ 1,192,127	1,152,403	$ 1,130,423	1,192,127	1,130,423
Net margin	18,414	24,410	18,167	21,980
Ending balance	$ 1,234,951	$ 1,216,537	$ 1,170,570	$ 1,152,403	$ 1,234,951	$ 1,170,570