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, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Supplemental Cash Flow Information [Abstract]
Income taxes paid, net	$ 22,336	$ 1,709	$ 23,752	$ 2,525
Interest paid	$ 2,062	$ 2,082	4,318	4,296
Cash Flow Non-cash Investing And Financing Activities Disclosure [Abstract]
Additions to property, plant and equipment in accounts payable			$ 5,960	$ 2,074