Consolidated Statements of Equity (Unaudited) - USD ($) $ in Thousands	Total	Postretirement Medical Benefit Plans	Executive Benefit Restoration Plan	Patronage capital	Accumulated other comprehensive income (loss)	Accumulated other comprehensive income (loss) Postretirement Medical Benefit Plans	Accumulated other comprehensive income (loss) Executive Benefit Restoration Plan	Noncontrolling interest
Equity at beginning of period at Dec. 31, 2022				$ 984,865	$ (468)			$ 126,180
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net margins attributable to the Association	$ (54,642)			(54,642)
Retirement of patronage capital				0
Unrealized gain (loss) on securities available for sale	16				16
Amortization of prior service credit into other income		$ (819)	$ 578			$ (819)	$ 578
Net comprehensive income attributable to noncontrolling interest	(4,918)							4,918
Equity distribution to noncontrolling interest								(949)
Equity at end of period at Jun. 30, 2023	1,059,679			930,223	(693)			130,149
Equity at beginning of period at Mar. 31, 2023				967,408	(527)			127,625
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net margins attributable to the Association	(37,185)			(37,185)
Retirement of patronage capital				0
Unrealized gain (loss) on securities available for sale	(45)				(45)
Amortization of prior service credit into other income		(410)	289			(410)	289
Net comprehensive income attributable to noncontrolling interest	(2,524)							2,524
Equity distribution to noncontrolling interest								0
Equity at end of period at Jun. 30, 2023	1,059,679			930,223	(693)			130,149
Equity at beginning of period at Dec. 31, 2023	1,118,011			984,581	(839)			134,269
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net margins attributable to the Association	(14,520)			(14,520)
Retirement of patronage capital				(82,200)
Unrealized gain (loss) on securities available for sale	65				65
Amortization of prior service credit into other income		(536)	509			(536)	509
Net comprehensive income attributable to noncontrolling interest	(5,497)							5,497
Equity distribution to noncontrolling interest								(10,028)
Equity at end of period at Jun. 30, 2024	1,016,798			887,861	(801)			129,738
Equity at beginning of period at Mar. 31, 2024				969,553	(949)			126,945
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net margins attributable to the Association	508			508
Retirement of patronage capital				(82,200)
Unrealized gain (loss) on securities available for sale	55				55
Amortization of prior service credit into other income		$ (127)	$ 220			$ (127)	$ 220
Net comprehensive income attributable to noncontrolling interest	(2,793)							2,793
Equity distribution to noncontrolling interest								0
Equity at end of period at Jun. 30, 2024	$ 1,016,798			$ 887,861	$ (801)			$ 129,738