Intangible Assets, Net (Details) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended		9 Months Ended		9 Months Ended		9 Months Ended		9 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2012	Oct. 31, 2011	Jan. 31, 2012	Apr. 30, 2012 Acquired Technology	Oct. 31, 2012 Acquired Technology Y	Jan. 31, 2012 Acquired Technology	Apr. 30, 2012 Customer Relationships	Oct. 31, 2012 Customer Relationships Y	Jan. 31, 2012 Customer Relationships	Oct. 31, 2012 Trade Names Y	Jan. 31, 2012 Trade Names	Oct. 31, 2012 Non-Competition Agreements Y	Jan. 31, 2012 Non-Competition Agreements	Oct. 31, 2012 Distribution Network Y	Jan. 31, 2012 Distribution Network	Oct. 31, 2012 Backlog Y	Jan. 31, 2012 Backlog	Oct. 31, 2012 In-Process Research and Development	Jan. 31, 2012 In-Process Research and Development
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross carrying amount	$ 341,585,000		$ 341,585,000		$ 341,467,000		$ 93,802,000	$ 94,027,000		$ 225,941,000	$ 225,554,000	$ 12,783,000	$ 12,824,000	$ 5,776,000	$ 5,779,000	$ 2,440,000	$ 2,440,000	$ 843,000	$ 843,000
Intangible assets, In-process research and development with indefinite lives																				2,500,000	2,500,000
Intangible assets, Finite and indefinite lives, Gross	344,085,000		344,085,000		343,967,000
Intangible assets, Accumulated amortization	189,832,000		189,832,000		159,737,000		60,947,000	49,732,000		112,614,000	95,173,000	10,395,000	9,805,000	4,279,000	3,656,000	1,535,000	1,352,000	62,000	19,000
Intangible assets, Net, Total	154,253,000		154,253,000		184,230,000
Intangible assets, Useful Life, Minimum, Years							2			4		3		3
Intangible assets, Useful Life, Maximum, Years							7			10		5		10
Intangible assets, Useful Life, Years																10		3
Amortization of intangible assets	9,800,000	9,400,000	29,500,000	25,700,000
Impairment of finite-lived intangible assets			0	0
Decrease in fair value of intangible assets						$ 300,000			$ 400,000