CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net unrealized gain, tax benefit (expense)	$ 64	$ 219	$ (308)	$ 1,024
Reclassification of net realized gain, tax expense	0	0	0	481
Pension and other postretirement benefits activity, tax expense	363	345	720	256
APS
Net unrealized gain, tax benefit (expense)	0	0	0	292
Reclassification of net realized gain, tax expense	0	0	0	481
Pension and other postretirement benefits activity, tax expense	$ 330	$ 298	$ 685	$ 174