Inventories (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Inventory, Net [Abstract]
Inventory Valuation Reserves	$ (624,457)				$ (624,457)	$ (397,478)
Lower of cost or market inventory valuation adjustment	$ (143,600)	$ (225,500)	$ 135,500	$ 6,500	$ 226,979	$ 397,478	$ 0
Excess of current cost over the LIFO value of inventory							273,000
Increase or reduction in cost of products sold							$ 9,200