Estimated Useful Life (Details)	12 Months Ended
Dec. 31, 2012
Building and improvements
Property, Plant and Equipment, Estimated Useful Lives	35 years
Office furnishings, leasehold improvements, computer equipment and computer software
Property, Plant and Equipment, Estimated Useful Lives	3-7 years
Transportation and construction equipment
Property, Plant and Equipment, Estimated Useful Lives	5-7 years

Describes the periods of time over which an entity anticipates to receive utility from its property, plant and equipment (that is, the periods of time over which an entity allocates the initial cost of its property, plant and equipment).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-URI http://asc.fasb.org/subtopic&trid=2155824

Name:	us-gaap_PropertyPlantAndEquipmentEstimatedUsefulLives
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration