Operating Segments - Reconciliation of Total Reportable Segments' Revenues and EBITDA to Consolidated Revenues and Consolidated Income (Loss) from Continuing Operations Before Taxes (Parenthetical) (Detail) - Tripwire [Member] $ in Millions	6 Months Ended
	Jun. 28, 2015 USD ($)
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Compensation expense	$ 9.2
Cost of sales related to adjustment of acquired inventory	$ 0.3