Statement Of Cash Flow Information - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Interest paid, net of interest capitalized	$ 15,943	$ 1,909	$ 7,369
Income taxes paid	$ 7,434	$ 8,856	$ 5,705