Reduction in Value of Assets (Components of the Expense) (Details) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2015
Reduction In Value Of Assets [Abstract]
Reduction in value of goodwill								$ 330,500	$ 1,326,701
Reduction in Value of Long-Lived Assets								143,803	330,194
Retirments of Long-Lived Assets								26,102	42,545
Reduction in value of assets related to sale of a business									39,447
Asset Impairment Charges, Total	$ 35,961	$ 1,963	$ 460,283	$ 2,198	$ 175,618	$ 755,632	$ 807,637	$ 500,405	$ 1,738,887