Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Cash Flow Information [Abstract]
Interest, Net of Capitalized Interest	$ 222,088	$ 197,383	$ 235,854
Income Taxes, Net of Refunds Received	41,108	342,741	294,739
Accrued Capital Expenditures	$ 416,000	972,000	731,000
Non-cash investing and financing activities from property exchanges.		$ 5,000	$ 5,000