Intangible Assets - Indefinite Lived Intangible Assets (Details) (USD $) In Thousands	Jun. 30, 2011		Dec. 31, 2010		Jun. 30, 2010
Indefinite-lived Intangible Assets by Major Class [Line Items]
Total unamortized intangible assets	$ 11,219		$ 11,219		$ 11,219
Construction [Member]
Indefinite-lived Intangible Assets by Major Class [Line Items]
Goodwill	9,900	[1]	9,900	[1]	9,900	[1]
Contractual Rights [Member]
Indefinite-lived Intangible Assets by Major Class [Line Items]
Use rights and other	$ 1,319		$ 1,319		$ 1,319

[1] Goodwill for all periods presented primarily relates to our Construction segment.