Consolidated Statements of Equity - USD ($) $ in Thousands	Patronage capital	Accumulated other comprehensive income (loss)	Noncontrolling interest	Total
Equity at beginning of year at Dec. 31, 2016	$ 961,364	$ (286)	$ 109,147
Change in Equity
Net margins attributable to the Association	28,317			$ 28,317
Unrealized gain on securities available for sale		46
Reclassification adjustment for actuarial gain on postretirement benefit obligation included in net income		(39)
Net comprehensive income attributable to noncontrolling interest			673	673
Equity at end of year at Jun. 30, 2017	989,681	(279)	109,820	1,099,222
Equity at beginning of year at Dec. 31, 2017	1,003,020	(210)	111,295	1,114,105
Change in Equity
Net margins attributable to the Association	12,472			12,472
Reclassification adjustment for unrealized gain on securities available for sale included in net income		(159)
Reclassification adjustment for actuarial gain on postretirement benefit obligation included in net income		(39)
Net comprehensive income attributable to noncontrolling interest			1,624	1,624
Equity distribution to noncontrolling interest			(2,858)
Equity at end of year at Jun. 30, 2018	$ 1,015,492	$ (408)	$ 110,061	$ 1,125,145