CONSOLIDATED STATEMENTS OF PATRONAGE CAPITAL AND MEMBERSHIP FEES - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Increase (Decrease) in Members' Capital
Net margin	$ 9,771	$ 25,958	$ (1,942)	$ 23,204	$ 57,781	$ 55,895	$ 54,461
Patronage Capital And Membership Fees
Increase (Decrease) in Members' Capital
Beginning balance		$ 1,072,642		$ 1,016,747	1,072,642	1,016,747	962,286
Net margin					57,781	55,895	54,461
Ending balance	$ 1,130,423		$ 1,072,642		$ 1,130,423	$ 1,072,642	$ 1,016,747