CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net unrealized loss, net of tax expense	$ 219	$ 0	$ 1,024	$ 0
Reclassification of net realized loss, net of tax benefit	0	(71)	(481)	(313)
Pension and other postretirement benefits activity, net of tax expense (benefit)	(345)	(290)	(256)	(72)
APS
Net unrealized loss, net of tax expense	0	0	292	0
Reclassification of net realized loss, net of tax benefit	0	(71)	(481)	(313)
Pension and other postretirement benefits activity, net of tax expense (benefit)	$ (298)	$ (249)	$ (174)	$ 48