Acquisitions (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 18, 2009 Telecast Fiber Systems [Member] m	Dec. 31, 2011 Thomas & Betts [Member]	Nov. 19, 2010 Thomas & Betts [Member]	Dec. 31, 2011 GarrettCom [Member]	Dec. 05, 2010 GarrettCom [Member]	Jan. 07, 2011 ICM Corp. [Member]	Apr. 01, 2011 Poliron Cabos Electricos Especiais LTDA [Member]	Aug. 31, 2011 Byres Security, Inc. [Member]	Dec. 31, 2011 Series of Individually Immaterial Business Acquisitions [Member]
Acquisitions (Textual) [Abstract]
Percentage of outstanding shares acquired								100.00%	100.00%
Acquisition price/cash paid at closing				$ 20,100,000		$ 77,200,000	$ 47,300,000	$ 56,600,000	$ 21,800,000	$ 28,700,000	$ 7,200,000
Acquisitions for cash	60,519,000	119,110,000	20,703,000
Fair value of acquired receivables					6,700,000		5,100,000
Gross contractual amount of acquired receivables					7,000,000		5,300,000
Estimated uncollectible acquired Accounts Receivable					300,000		200,000
Cash paid subsequent to closing							4,100,000
Remaining cash to be paid							5,200,000
Distance of signal transmission				100
Goodwill	27,891,000	55,299,000			29,335,000	29,335,000	24,059,000	24,059,000				27,800,000
Business acquisition purchase price allocation intangible asset						$ 22,900,000		$ 19,200,000				$ 21,300,000