Acquisitions (Details) (USD $)	0 Months Ended		3 Months Ended
	Mar. 04, 2015	Jan. 13, 2015	Apr. 26, 2015	Apr. 27, 2014	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			$ 35,000,000	$ 0
Goodwill			329,703,000		280,319,000
Triune Systems [Member]
Business Acquisition [Line Items]
Purchase price	45,000,000
Cash paid to to acquire business	35,000,000
Cash to be paid in six months from closing date	10,000,000
Fair value of earn-out liability			16,700,000
Goodwill			49,400,000
Triune Systems [Member] | Core Technologies [Member]
Business Acquisition [Line Items]
Acquisition consideration allocated to finite-lived intangible assets			10,000,000
Triune Systems [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Acquisition consideration allocated to finite-lived intangible assets			2,000,000
Triune Systems [Member] | Other liabilities [Member]
Business Acquisition [Line Items]
Earn-out liability booked			16,200,000
Triune Systems [Member] | Earn-out Payable Within First Three Fiscal Years Of Acquisition Date [Member]
Business Acquisition [Line Items]
Potential payments under earn-out arrangements, high estimate	70,000,000
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
EnVery [Member]
Business Acquisition [Line Items]
Cash paid to to acquire business		4,900,000
Goodwill			3,400,000
EnVery [Member] | Core Technologies [Member]
Business Acquisition [Line Items]
Acquisition consideration allocated to finite-lived intangible assets			$ 1,400,000