Uncompleted Contracts - Gross and Net Amounts of Uncompleted Contracts (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Jun. 30, 2017
Disclosure Customer Contracts Additional Information [Abstract]
Costs incurred and estimated earnings recognized on uncompleted contracts	$ 2,152,981	$ 1,919,054
Billings on uncompleted contracts	2,155,136	1,903,001
Total	(2,155)	16,053
Shown on balance sheet as:
Costs and estimated earnings in excess of billings on uncompleted contracts	64,221	91,180
Billings on uncompleted contracts in excess of costs and estimated earnings	$ 66,376	$ 75,127

Liability attributable to (i) billings in excess of costs under the percentage of completion contract accounting method representing the difference between contractually invoiced amounts (billings) and revenue recognized based, for example, on costs incurred to estimated total costs at period end or (ii) contractually invoiced amounts (billings) in excess of costs incurred and accumulated under the completed contract accounting method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 35
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=68068069&loc=d3e57807-111642

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 35
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=68068069&loc=d3e57788-111642

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 35
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68068069&loc=d3e57795-111642

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