Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Interest Expense	$ 219,198	$ 220,042	$ 248,344
Gains (Losses) on Extinguishment of Debt	0	0	16,090
Long-term Debt	3,118,920	3,127,726
Less amounts due in one year	(2,957)	(4,126)
Long-Term Debt	3,115,963	3,123,600
Senior Notes Due April 2017 at 8.00%
Debt Instrument [Line Items]
Long-term Debt	1,500,000	1,500,000
Interest rate stated percentage	8.00%
Debt Instrument, Face Amount	1,500,000
Senior notes due April 2020 at 8.25%
Debt Instrument [Line Items]
Long-term Debt	1,250,000	1,250,000
Interest rate stated percentage	8.25%
Debt Instrument, Face Amount	1,250,000
Senior notes due March 2021 at 6.375%
Debt Instrument [Line Items]
Long-term Debt	250,000	250,000
Interest rate stated percentage	6.375%
Debt Instrument, Face Amount	250,000
Baltimore Port Facility revenue bonds in series due September 2025 at 5.75%
Debt Instrument [Line Items]
Long-term Debt	102,865	102,865
Advance royalty commitments
Debt Instrument [Line Items]
Long-term Debt	11,182	19,103
Note due through December 2012 at 6.10%
Debt Instrument [Line Items]
Long-term Debt	$ 4,873	$ 5,758