Acquisitions (Details) (USD $)					6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended				6 Months Ended					6 Months Ended					12 Months Ended				6 Months Ended	12 Months Ended
	Dec. 31, 2011		Jun. 25, 2011		Dec. 31, 2011 Intellectual property [Member] years	Jun. 25, 2011 Intellectual property [Member] years	Dec. 31, 2011 Customer relationships [Member] years	Jun. 25, 2011 Customer relationships [Member] years	Dec. 31, 2011 Trademark [Member] years	Jun. 25, 2011 Trademark [Member] years	Jun. 25, 2011 Backlog [Member] years	Dec. 31, 2011 Sensor Dynamics [Member]	Jul. 18, 2011 Sensor Dynamics [Member]	Dec. 31, 2011 Sensor Dynamics [Member] Intellectual property [Member] years	Dec. 31, 2011 Sensor Dynamics [Member] Customer relationships [Member] years	Dec. 31, 2011 Sensor Dynamics [Member] Trademark [Member] years	Dec. 31, 2011 Other Acquisition [Member]		Dec. 31, 2011 Other Acquisition [Member] Intellectual property [Member] years	Dec. 31, 2011 Other Acquisition [Member] Customer relationships [Member] years	Dec. 31, 2011 Other Acquisition [Member] Trademark [Member] years	Jun. 25, 2011 Phyworks [Member]	Sep. 07, 2010 Phyworks [Member]	Jun. 25, 2011 Phyworks [Member] Intellectual property [Member] years	Jun. 25, 2011 Phyworks [Member] Customer relationships [Member] years	Jun. 25, 2011 Phyworks [Member] Trademark [Member] years	Jun. 25, 2011 Phyworks [Member] Backlog [Member] years	Dec. 31, 2011 Other Acquisitions [Member] acquisitions	Jun. 25, 2011 Other Acquisitions [Member] acquisitions		Jun. 25, 2011 Other Acquisitions [Member] Intellectual property [Member] years	Jun. 25, 2011 Other Acquisitions [Member] Customer relationships [Member] years	Jun. 25, 2011 Other Acquisitions [Member] Trademark [Member] years	Jun. 25, 2011 Other Acquisitions [Member] Backlog [Member] years
Business Acquisition, Purchase Price Allocation [Abstract]
Tangible assets	$ 19,851,000		$ 6,338,000									$ 18,692,000					$ 1,159,000					$ 5,676,000							$ 662,000
Debt assumed	(29,078,000)											(29,078,000)					0
Liabilities assumed			(18,342,000)																			(17,524,000)							(818,000)
Business Acquisition Purchase Price Allocation Other Liabilities Assumed	42,288,000											37,559,000					4,729,000
Net liabilities assumed	51,515,000		12,004,000									47,945,000					3,570,000					11,848,000							156,000
Amortizable intangible assets	38,740,000		52,550,000		31,740,000	48,850,000	6,600,000	1,600,000	400,000	200,000	1,900,000	20,900,000		16,400,000	4,100,000	400,000	17,840,000		15,340,000	2,500,000	0	50,800,000		47,100,000	1,600,000	200,000	1,900,000		1,750,000		1,750,000	0	0	0
In-process research and development (IPR&D)	19,600,000		8,380,000									19,600,000					0					5,800,000							2,580,000
Goodwill	168,986,000	[1]	40,793,000	[2]								130,594,000					38,392,000					26,606,000							14,187,000	[2]
Total purcahse price	175,811,000	[1]	89,719,000	[2]								123,149,000					52,662,000	[1]				71,358,000							18,361,000	[2]
Fair value of contingent consideration																	11,400,000												8,800,000
Total cash consideration													123,100,000				41,300,000												8,200,000
Acquired finite-lived intangible asset, Weighted Average Useful Life (in Years)					8.1	4.9	5.5	5	3	1	1.3			7	7	3			9.2	3	0.0			5	5	1	1.3				3	0	0	0
Goodwill amount expected to be deductible for tax purposes																							0
Number of businesses acquired																												3	2
Cash acquired																													400,000
Business acquisition contingent consideration potential cash payment																	7,400,000												12,500,000
Business acquisition,cash paid for contingent consideration																												$ 1,800,000

[1] Includes $11.4 million of contingent consideration relating to the other acquisitions.

[2] Includes $8.8 million of contingent consideration relating to one of the other acquisitions