Supplemental Cash Flow and Non-Cash Information (Table Of Supplmental Cash Flow Information) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Supplemental Cash Flow Information [Abstract]
Income taxes paid, net	$ 2,091	$ 15,544	$ 16,375	$ 39,296
Interest paid	$ 2,333	$ 1,845	6,355	6,163
Cash Flow Non-cash Investing And Financing Activities Disclosure [Abstract]
Additions to property, plant and equipment in accounts payable			$ 2,370	$ 6,629