Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended		6 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012	Oct. 02, 2011	Jul. 01, 2012 Trapeze Networks, Inc [Member]	Sep. 30, 2012 Communications cable operation in Phoenix, Arizona [Member]	Sep. 30, 2012 Communications cable operation in Phoenix, Arizona [Member]	Sep. 30, 2012 Standby letters of credit [Member]	Sep. 30, 2012 Bank guaranties [Member]	Sep. 30, 2012 Surety bonds [Member]
Loss Contingencies [Line Items]
Reporting Period		274 days	275 days
Impact of reclassifications to reported net income		$ 0
Original maturity period of cash and cash equivalents		Three months or less
Fair value of cash and cash equivalents based on quoted market prices in active markets Level 1 valuation	177,200,000	177,200,000
Contingency accrual at carrying value							6,500,000	5,000,000	1,700,000
Income from Discontinued operations				152,100,000
Cash received on transaction with Trapeze network				136,900,000
Other income related to escrow				15,200,000
Interest and losses related to discontinued operations	7,000,000	7,000,000			14,100,000	14,100,000
Loss from discontinued operations, net of tax	4,300,000	4,300,000			4,000,000	2,600,000
Receivables, net	$ 8.0	$ 8.0