Business Acquisition - Recognized Identified Assets Acquired and Liabilities Assumed (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 31, 2012
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill	$ 33,798	$ 33,798	$ 33,798
West Construction, Inc.
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Fixed assets, including inventory				5,936
Seller receivables				1,425
Intangible assets				702
Goodwill				2,649
Payable to Seller				(1,425)
Noncontrolling interest				(16)
Total recognized identifiable assets acquired, goodwill, and liabilities assumed, net				$ 9,271