Uncompleted Contracts - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Mar. 31, 2017	Mar. 31, 2017	Mar. 31, 2018	Jun. 30, 2017
Customer Contracts [Line Items]
Contract Receivable Retainage, Due in Next Twelve Months			$ 23.2	$ 54.3
Contract Receivable Retainage, Due after Next Twelve Months				$ 1.9
Change In Accounting Estimate, Financial Effect, Operating Income	$ (18.9)	$ (13.7)

Change In Accounting Estimate, Financial Effect, Operating Income

No definition available.

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Period Type:	duration

- Definition

[Line Items] for Customer Contracts [Table]

+ References

No definition available.

+ Details

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- Definition

Amount billed to customers under long-term contracts or programs that have been withheld because of retainage provisions in a contract to be collected after the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ 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 210.5-02.3(c)(4))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 910
-SubTopic 310
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=68065756&loc=d3e49370-109356

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount billed to customers under long-term contracts or programs that have been withheld because of retainage provisions in a contract to be collected in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ 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(3)(c))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 910
-SubTopic 310
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68065756&loc=d3e49370-109356

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant