Acquisitions (Details) - USD ($)		1 Months Ended	3 Months Ended
	Mar. 04, 2015	Sep. 30, 2015	Apr. 30, 2017	Jul. 31, 2016
Business Acquisition [Line Items]
Effective date of acquisition	Mar. 04, 2015
Name of acquired entity	Triune Systems, L.L.C.
Potential payments under earn-out arrangements, high estimate	$ 70,000,000
Triune Systems [Member]
Business Acquisition [Line Items]
Purchase price	45,000,000
Cash paid to to acquire business	35,000,000	$ 9,500,000		$ 500,000
Additional cash consideration	10,000,000
Earn-out liability			$ 0
Triune Systems [Member] | Earn-out Payable Within First Three Fiscal Years Of Acquisition Date [Member]
Business Acquisition [Line Items]
Period over which contingent consideration will be paid			3 years
Triune Systems [Member] | Additional Earn-out Payable After Third Fiscal Year From Acquisition Date [Member]
Business Acquisition [Line Items]
Potential payments under earn-out arrangements, high estimate	$ 16,000,000