Investments in Unconsolidated Affiliates (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Assets:
Current assets	$ 25,048
Noncurrent assets	156,628
Total assets	181,676
Liabilities:
Current liabilities	32,927
Noncurrent liabilities	73,985
Total liabilities	106,912
Results of operations:
Revenue	17,788	23,245
Net income	$ (9,353)	$ (8,299)