Consolidated Statement of Equity - USD ($) $ in Thousands	Patronage capital	Accumulated other comprehensive income (loss)	Noncontrolling interest	Total
Equity at beginning of period at Dec. 31, 2015	$ 952,082	$ 589	$ 108,757
Change in Equity
Net margins attributable to the Association	20,070			$ 20,070
Retirement of patronage capital	(12,466)
Unrealized gain (loss) on securities available for sale		(1)
Amortization of actuarial gain on postretirement benefit obligation included in net income		(45)
Net income attributable to noncontrolling interest			181	181
Equity distribution to noncontrolling interest			(59)
Equity at end of period at Jun. 30, 2016	959,686	543	108,879	1,069,108
Equity at beginning of period at Dec. 31, 2016	961,364	(286)	109,147	1,070,225
Change in Equity
Net margins attributable to the Association	28,317			28,317
Unrealized gain (loss) on securities available for sale		46
Amortization of actuarial gain on postretirement benefit obligation included in net income		(39)
Net income attributable to noncontrolling interest			673	673
Equity at end of period at Jun. 30, 2017	$ 989,681	$ (279)	$ 109,820	$ 1,099,222