Inventories (Schedule Of Inventories) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2018	Dec. 31, 2017
Inventories:
Raw materials and supplies		$ 49,392	$ 39,434
Work in process		93,578	85,852
Finished goods		59,548	48,865
Total		$ 202,518	$ 174,151
Inventory write-downs	$ 1,300