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Commitments and Contingencies - Narrative (Details) | 12 Months Ended
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Sep. 30, 2017 USD ($)
Guarantor Obligations [Line Items] |
Additional bonding capacity | $ 531,200,000
Liquidated damages | 2,300,000
Probable liquidated damages | 1,200,000
Loss contingency, estimate of actual or projected loss | 1,200,000
Facility Agreement | Powell (UK) Limited |
Guarantor Obligations [Line Items] |
Guarantee liability | 4,400,000
Revolving credit facility | 6,700,000
Amount of credit facility remaining borrowing capacity | 2,300,000
Surety Bond |
Guarantor Obligations [Line Items] |
Guarantee liability | 218,800,000
U.S. Revolver |
Guarantor Obligations [Line Items] |
Revolving credit facility | 75,000,000
Amount of credit facility remaining borrowing capacity | 50,900,000
U.S. Revolver | Financial Standby Letter of Credit |
Guarantor Obligations [Line Items] |
Guarantee liability | $ 24,100,000

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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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