Investments in Unconsolidated Affiliates (Details 2) (Other Unconsolidated Investments [Member], USD $) In Thousands	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010
Other Unconsolidated Investments [Member]
Summarized financial information of other unconsolidated investments
Operating revenue	$ 14,029	$ 17,024
Operating expenses	(11,883)	(14,173)
Depreciation and amortization	(756)	(759)
Other expense, net	3	3
Net income	1,393	2,097
Current assets	10,728	4,129
Noncurrent assets	215,259	21,198
Current liabilities	(25,111)	(6,041)
Noncurrent liabilities	(898)	(60)
Net assets	$ 199,978	$ 19,226

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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