CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net unrealized loss, net of tax expense	$ 292	$ 0
Reclassification of net realized loss, net of tax benefit	394	108
Pension and other postretirement benefits activity, net of tax expense (benefit)	108	288
APS
Net unrealized loss, net of tax expense	292	0
Reclassification of net realized loss, net of tax benefit	394	108
Pension and other postretirement benefits activity, net of tax expense (benefit)	$ 237	$ 247