Acquisitions (Identifiable Intangible Assets Acquired) (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended
	Jan. 13, 2015	Dec. 30, 2014	Oct. 29, 2014	Jul. 07, 2014
Tew Holdings, LTD [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 14,048
Tew Holdings, LTD [Member] | Trade name [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	870
Tew Holdings, LTD [Member] | Customer relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	10,035
Tew Holdings, LTD [Member] | Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	2,480
Tew Holdings, LTD [Member] | Non-compete agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	663
Chemtec Energy Services, LLC [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired		33,130
Chemtec Energy Services, LLC [Member] | Trade name [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired		3,149
Chemtec Energy Services, LLC [Member] | Customer relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired		23,934
Chemtec Energy Services, LLC [Member] | Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired		4,930
Chemtec Energy Services, LLC [Member] | Non-compete agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired		1,117
FWO [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired			419
FWO [Member] | Trade name [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired			0
FWO [Member] | Customer relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired			34
FWO [Member] | Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired			341
FWO [Member] | Non-compete agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired			44
Carr Concrete [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired				1,348
Carr Concrete [Member] | Trade name [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired				613
Carr Concrete [Member] | Customer relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired				524
Carr Concrete [Member] | Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired				87
Carr Concrete [Member] | Non-compete agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired				$ 124