Intangible Assets - Indefinite Lived Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Indefinite-lived Intangible Assets by Major Class [Line Items]
Finite-Lived Intangible Assets, Gross	$ 48,570	$ 49,370	$ 34,370
Goodwill	53,799	55,419	9,900
Construction [Member]
Indefinite-lived Intangible Assets by Major Class [Line Items]
Goodwill	28,398	29,190	6,937
Large Project Construction [Member]
Indefinite-lived Intangible Assets by Major Class [Line Items]
Goodwill	23,287	24,115	849
Construction Materials [Member]
Indefinite-lived Intangible Assets by Major Class [Line Items]
Goodwill	2,114	2,114	2,114
Use Rights [Member]
Indefinite-lived Intangible Assets by Major Class [Line Items]
Finite-Lived Intangible Assets, Gross	$ 400	$ 400	$ 400