Equity Investees (Schedule Of Balance Sheet Information For Equity Investees) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Equity Method Investments and Joint Ventures [Abstract]
Current assets	$ 81,686	$ 74,906
Fixed assets, net	896,395	832,525
Other assets	9,416	10,202
Total assets	987,497	917,633
Current liabilities	66,030	112,321
Other liabilities	146,233	134,731
Equity	775,234	670,581
Total liabilities and equity	$ 987,497	$ 917,633