Subsequent Events (Narrative) (Details) (Carr Concrete Corporation [Member], Subsequent Event [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
Carr Concrete Corporation [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Business Acquisition, Effective Date of Acquisition	Jul. 07, 2014
Business Acquisition, Name of Acquired Entity	Carr Concrete Corporation (Carr)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	$ 12,300
Business Combination, Indemnification Assets, Amount as of Acquisition Date	1,000
Business Acquisition, Net Working Capital Target	2,678
Business Acquisition, Transaction Costs	$ 100