Inventories (Schedule Of Inventory) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Inventory, Net [Abstract]
Finished products	$ 253,338	$ 300,909
Feedstock, additives, and chemicals	106,435	158,635
Materials and supplies	74,287	66,232
Inventories	$ 434,060	$ 525,776