Mergers and Acquisitions (Tables)

12 Months Ended

Dec. 31, 2012

Acquisitions Material in the Aggregate [Member]

Mergers and Acquisitions [Abstract]

Unaudited Pro Forma Summary Financial Information

The following unaudited pro forma summary financial information presents the operating results of the combined Company for the twelve months ended December 31, 2011 and 2010 assuming that the acquisitions occurred on January 1, 2010. This unaudited pro forma summary financial information is presented for informational purposes only and is not indicative either of the operating results that actually would have occurred had the acquisitions been completed on January 1, 2010, or of future results.

Pro Forma (unaudited)	Year ended December 31,
	2011		2010
(in thousands, except per share data)
Revenues	$	3,894,867	$	3,898,519
Income from Construction Operations	$	178,631	$	197,014
Net Income	$	88,123	$	109,598
Basic earnings per common share	$	1.87	$	2.28
Diluted earnings per common share	$	1.84	$	2.25

GreenStar Services Corporation [Member]

Mergers and Acquisitions [Abstract]

Unaudited Pro Forma Summary Financial Information

The following unaudited pro forma summary financial information presents the operating results of the combined Company for the twelve months ended December 31, 2011 and 2010 assuming that the merger occurred on January 1, 2010. This unaudited pro forma summary financial information is presented for informational purposes only and is not indicative either of the operating results that actually would have occurred had the merger been completed on January 1, 2010, or of future results.

Pro Forma (unaudited)	Year ended December 31,
	2011		2010
(in thousands, except per share data)
Revenues	$	4,068,804	$	3,778,958
Income from Construction Operations	$	207,579	$	180,863
Net Income	$	108,712	$	105,074
Basic earnings per common share	$	2.30	$	2.18
Diluted earnings per common share	$	2.27	$	2.16

Lunda Construction Company [Member]

Mergers and Acquisitions [Abstract]

Unaudited Pro Forma Summary Financial Information

The following unaudited pro forma summary financial information presents the operating results of the combined Company for the twelve months ended December 31, 2011 and 2010 assuming that the acquisition occurred on January 1, 2010. This unaudited pro forma summary financial information is presented for informational purposes only and is not indicative either of the operating results that actually would have occurred had the acquisitions been completed on January 1, 2010, or of future results.

Pro Forma (unaudited)	Year ended December 31,
	2011		2010
(in thousands, except per share data)
Revenues	$	3,872,694	$	3,558,317
Income from Construction Operations	$	191,565	$	246,396
Net Income	$	98,270	$	146,708
Basic earnings per common share	$	2.08	$	3.05
Diluted earnings per common share	$	2.05	$	3.02