Goodwill (Details)	3 Months Ended	6 Months Ended
	Apr. 30, 2016 USD ($) operating_segment	Jan. 31, 2016 USD ($) operating_segment	Feb. 23, 2016 USD ($)	Jul. 31, 2015 USD ($)
Goodwill [Line Items]
Number of Reportable Segments | operating_segment	2	3
Reallocation to new segments	$ 137,354,000
Goodwill	264,503,000	$ 137,354,000		$ 137,354,000
Additions resulting from TCS acquisition
Goodwill [Line Items]
Goodwill	127,149,000		$ 127,149,000
Commercial Solutions Segment
Goodwill [Line Items]
Reallocation to new segments	102,100,000
Goodwill	212,137,000
Commercial Solutions Segment | Additions resulting from TCS acquisition
Goodwill [Line Items]
Goodwill	110,037,000
Government Solutions Segment
Goodwill [Line Items]
Reallocation to new segments	35,254,000
Goodwill	52,366,000
Government Solutions Segment | Additions resulting from TCS acquisition
Goodwill [Line Items]
Goodwill	$ 17,112,000