Goodwill and Intangible Assets (Schedule of Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Goodwill
Gross Goodwill Balance		$ 1,065,741
Accumulated Impairment		(487,985)
Goodwill	585,006	577,756
Civil [Member]
Goodwill
Gross Goodwill Balance		429,893
Accumulated Impairment		(55,740)
Goodwill	415,358	374,153
Building [Member]
Goodwill
Gross Goodwill Balance		420,267
Accumulated Impairment		(409,765)
Goodwill	13,455	10,502
Specialty Contractors [Member]
Goodwill
Gross Goodwill Balance		148,943
Goodwill	156,193	148,943
Management Services [Member]
Goodwill
Gross Goodwill Balance		66,638
Accumulated Impairment		(22,480)
Goodwill		$ 44,158

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

+ Details

Name:	us-gaap_Goodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a,h)

-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

+ Details

Name:	us-gaap_GoodwillGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

+ Details

Name:	us-gaap_GoodwillImpairedAccumulatedImpairmentLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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