Business Acquisition - Narrative (Details) (USD $)	12 Months Ended			0 Months Ended	1 Months Ended	12 Months Ended				12 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended
	Dec. 31, 2012 entity	Dec. 31, 2011	Dec. 31, 2010	Oct. 31, 2012 West Construction, Inc.	Oct. 31, 2012 West Construction, Inc.	Dec. 31, 2012 West Construction, Inc.	Dec. 31, 2012 Minimum West Construction, Inc.	Dec. 31, 2012 Maximum West Construction, Inc.	Oct. 31, 2012 Maximum West Construction, Inc.	Dec. 31, 2012 Construction equipment Minimum	Oct. 31, 2012 Construction equipment Minimum West Construction, Inc.	Dec. 31, 2012 Construction equipment Maximum	Oct. 31, 2012 Construction equipment Maximum West Construction, Inc.	Oct. 31, 2012 Trade name West Construction, Inc.	Oct. 31, 2012 Backlog West Construction, Inc.
Business Combination, Assets and Liabilities Arising from Contingencies [Abstract]
Cash paid to acquire business				$ 9,000,000
Additional potential cash payment									1,000,000
Percent of EBITDA to base the additional potential cash payment					20.00%
Additional potential cash payment consideration, period following acquisition close taken into consideration				12 months
Contingent consideration, at fair value				271,000	271,000
Number of foreign entities the Company acquired ownership interest during period	1
Consulting and sales agreement entered into with the acquiree company personnel, contract term	2 years
Lease agreement with the Seller company, lease term						3 years
Acquired intangible assets				702,000	702,000									332,000	370,000
Acquired intangible assets useful life							1 year	3 years						1 year	3 years
Property and equipment useful life										3 years	3 years	15 years	15 years
Goodwill	$ 34,817,000	$ 32,168,000	$ 32,168,000	$ 2,649,000	$ 2,649,000
Goodwill acquired during period, amortization period for tax purposes					15 years