Stock-Based Compensation - Expense Recognized (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Stock-based compensation included in indirect costs and selling expense:
Total stock-based compensation related to RSUs included in indirect costs and selling expense	$ 5,557	$ 4,856	$ 16,114	$ 13,329
Income tax benefit recognized for stock-based compensation expense	$ 1,490	$ 1,719	$ 5,435	$ 4,897

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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