Acquisitions (Details) - USD ($) $ in Thousands			1 Months Ended	3 Months Ended	6 Months Ended
	Mar. 04, 2015	Jan. 13, 2015	Sep. 30, 2015	Jul. 31, 2016	Jul. 31, 2016	Jul. 26, 2015	Jan. 31, 2016	Jan. 25, 2015
Business Acquisition [Line Items]
Effective date of acquisition	Mar. 04, 2015	Jan. 13, 2015
Name of acquired entity	Triune Systems, L.L.C.	EnVerv
Borrowings under line of credit	$ 35,000				$ 0	$ 35,000
Potential payments under earn-out arrangements, high estimate	70,000
Goodwill				$ 329,703	329,703		$ 329,703
Triune Systems [Member]
Business Acquisition [Line Items]
Purchase price	45,000
Cash paid to to acquire business	35,000		$ 9,500
Additional cash consideration	10,000			500
Goodwill	49,384
Earn-out liability				$ 0	$ 0
Triune Systems [Member] | Core Technologies [Member]
Business Acquisition [Line Items]
Acquisition consideration allocated to finite-lived intangible assets	10,000
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					2 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
EnVerv [Member]
Business Acquisition [Line Items]
Cash paid to to acquire business		$ 4,900
Goodwill								$ 3,400
EnVerv [Member] | Core Technologies [Member]
Business Acquisition [Line Items]
Acquisition consideration allocated to finite-lived intangible assets								$ 1,400