Supplemental Cash Flow And Non-Cash Information (Schedule Of Supplemental Cash Flow Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Information [Abstract]
Income taxes paid, net	$ 6,453	$ 7,865	$ 8,561
Interest paid	8,698	8,305	2,472
Cash Flow Non-cash Investing And Financing Activities Disclosure [Abstract]
Additions to property, plant and equipment in accounts payable	$ 7,761	$ 2,111	$ 2,761