Other Long-Term Liabilities (Schedule Of Other Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Other Long-Term Liabilities [Abstract]
Asset retirement obligations	$ 115,550	$ 121,534	$ 131,031
Long-term derivative liabilities	7,586	9,245
Other	4,653	591
Total Other Liabilities	$ 127,789	$ 131,370