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	37,809			$ 37,809
Retirement of patronage capital	(12,466)
Unrealized gain on securities available for sale		35
Amortization of actuarial gain on postretirement benefit obligation included in net income		(68)
Net income attributable to noncontrolling interest			313	313
Equity distribution to noncontrolling interest			(59)
Equity at end of period at Sep. 30, 2016	977,425	556	109,011	1,086,992
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	69,115			69,115
Unrealized gain on securities available for sale		94
Amortization of actuarial gain on postretirement benefit obligation included in net income		(59)
Net income attributable to noncontrolling interest			1,409	1,409
Equity at end of period at Sep. 30, 2017	$ 1,030,479	$ (251)	$ 110,556	$ 1,140,784