Commitments and Contingencies - Narrative (Details) - USD ($) $ in Thousands	Dec. 17, 2014	Nov. 13, 2014	Oct. 25, 2015	Jul. 26, 2015	Mar. 04, 2015	Jan. 25, 2015
Loss Contingencies [Line Items]
Earn-out liability booked			$ 8,135			$ 1,771
Amount expected to be settled within twelve months			1,684			0
Cycleo [Member]
Loss Contingencies [Line Items]
Potential payments under earn-out arrangements, high estimate			16,000
Earn-out liability booked			5,315			1,771
Amount expected to be settled within twelve months			1,684			0
Triune Systems [Member]
Loss Contingencies [Line Items]
Earn-out liability booked			2,820	$ 16,900		0
Amount expected to be settled within twelve months			0			0
Environmental Issue
Loss Contingencies [Line Items]
Range of possible loss, minimum			5,300			2,700
Range of possible loss, maximum			7,500			$ 5,700
Environmental loss contingency accrual, at carrying value			$ 5,300
Commercial Dispute
Loss Contingencies [Line Items]
Name of plaintiff	Semtech	Intrigo
Loss contingency, damages sought	$ 3,700	$ 2,700
Earn-out Payable Within First Three Fiscal Years Of Acquisition Date [Member] | Triune Systems [Member]
Loss Contingencies [Line Items]
Potential payments under earn-out arrangements, high estimate					$ 70,000
Additional Earn-out Payable After Third Fiscal Year From Acquisition Date [Member] | Triune Systems [Member]
Loss Contingencies [Line Items]
Potential payments under earn-out arrangements, high estimate					$ 16,000