Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Consolidated Statements of Comprehensive Income
Net margins including noncontrolling interest	$ 49,663	$ 46,021	$ 63,804
Other comprehensive income (loss):
Unrealized gain on securities available for sale			43
Unrecognized actuarial gain (loss) on postretirement benefit obligation	(1,341)	456	106
Reclassification of unrealized gain on securities available for sale included in net margin		(159)
Amortization of actuarial (gain) loss on postretirement benefit obligation included in net margin	(338)	288	(73)
Unrecognized prior service cost	(214)
Other comprehensive income (loss)	(1,893)	585	76
Comprehensive income (loss) including noncontrolling interest	47,770	46,606	63,880
Net comprehensive income attributable to noncontrolling interest	(4,354)	(3,287)	(2,148)
Comprehensive income (loss) attributable to the Association	$ 43,416	$ 43,319	$ 61,732