Commitments and Contingencies (Narrative) (Details) (USD $)	Dec. 31, 2014
Guarantee Obligations [Line Items]
Additional bonding capacity	$ 288,100,000
Powell (UK) Limited
Guarantee Obligations [Line Items]
Guarantee liability	3,900,000
Revolving credit facility	15,500,000
Amount of credit facility remaining borrowing capacity	11,600,000
Financial Standby Letter of Credit
Guarantee Obligations [Line Items]
Guarantee liability	18,300,000
Performance Guarantee
Guarantee Obligations [Line Items]
Guarantee liability	$ 311,900,000

Commitments and contingencies additional bonding capacity.

No definition available.

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- Definition

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

+ Details

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- Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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- Details

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