Discontinued Operations - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Discontinued Operations [Line Items]
Gain/Loss on Disposal of Discontinued Operations, net of tax	$ 124,697,000	$ 9,783,000	$ 134,480,000		$ 44,847,000
Net current liability of discontinued operations	86,860,000		86,860,000	16,328,000
Receivable, net	300,864,000		300,864,000	288,543,000
Income/Loss from Discontinued Operations, before tax			25,459,000	20,647,000	777,000
Thermax and Raydex [Member]
Discontinued Operations [Line Items]
Amount received in cash from the sales of business units			265,600,000
Gain/Loss on Disposal of Discontinued Operations, before tax			211,600,000
Gain/Loss on Disposal of Discontinued Operations, net of tax			124,700,000
Net current liability of discontinued operations	86,900,000		86,900,000
Income/Loss from Discontinued Operations, before tax			21,479,000	21,792,000	12,546,000
Trapeze [Member]
Discontinued Operations [Line Items]
Amount received in cash from the sales of business units					152,100,000
Gain/Loss on Disposal of Discontinued Operations, before tax			7,000,000		88,300,000
Gain/Loss on Disposal of Discontinued Operations, net of tax			4,300,000		44,800,000
Amount received in cash at the end of transaction					136,900,000
Amount in escrow as partial security for Company's indemnity obligations under transaction's purchase and sale agreement					15,200,000
Receivable, net	8,000,000		8,000,000
Expense related to the sale of Trapeze				200,000
Income/Loss from Discontinued Operations, before tax				(196,000)	(10,791,000)
Communications cable operation in Phoenix, Arizona [Member]
Discontinued Operations [Line Items]
Income/Loss from Discontinued Operations, net of tax			2,600,000	700,000	600,000
Income/Loss from Discontinued Operations, before tax				900,000	1,000,000
Communications cable operation in Phoenix, Arizona [Member] | Reversal of accrued interest and penalties [Member]
Discontinued Operations [Line Items]
Income/Loss from Discontinued Operations, before tax			4,000,000
Communications cable operation in Phoenix, Arizona [Member] | Uncertain tax positions liability [Member]
Discontinued Operations [Line Items]
Gain/Loss on Disposal of Discontinued Operations, net of tax			$ 14,100,000