Intangible Assets - Indefinite Lived Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Indefinite-lived Intangible Assets by Major Class [Line Items]
Total unamortized intangible assets	$ 10,293	$ 10,293	$ 11,219
Contractual Rights [Member]
Indefinite-lived Intangible Assets by Major Class [Line Items]
Use rights and other	393	393	1,319
Construction [Member]
Indefinite-lived Intangible Assets by Major Class [Line Items]
Goodwill	$ 9,900	$ 9,900	$ 9,900