Supplemental Cash Flow and Non-Cash Information (Table Of Supplmental Cash Flow Information) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Supplemental Cash Flow Information [Abstract]
Income taxes paid, net	$ 932	$ 12,042	$ 2,967	$ 14,284
Interest paid	$ 2,488	$ 2,032	4,427	4,022
Cash Flow Non-cash Investing And Financing Activities Disclosure [Abstract]
Additions to property, plant and equipment in accounts payable			$ 3,677	$ 5,660