Intangible Assets, Net (Details) (USD $)	3 Months Ended		6 Months Ended			3 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended		6 Months Ended		6 Months Ended		6 Months Ended		6 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2012	Jul. 31, 2011	Jan. 31, 2012	Apr. 30, 2012 Acquired Technology	Jul. 31, 2012 Acquired Technology Y	Jan. 31, 2012 Acquired Technology	Apr. 30, 2012 Customer Relationships	Jul. 31, 2012 Customer Relationships Y	Jan. 31, 2012 Customer Relationships	Jul. 31, 2012 Trade Names Y	Jan. 31, 2012 Trade Names	Jul. 31, 2012 Non-Competition Agreements Y	Jan. 31, 2012 Non-Competition Agreements	Jul. 31, 2012 Distribution Network Y	Jan. 31, 2012 Distribution Network	Jul. 31, 2012 Backlog Y	Jan. 31, 2012 Backlog	Jul. 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	$ 476,401,000		$ 476,401,000		$ 478,653,000		$ 190,864,000	$ 192,029,000		$ 260,425,000	$ 261,338,000	$ 16,067,000	$ 16,224,000	$ 5,762,000	$ 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	478,901,000		478,901,000		481,153,000
Intangible assets, Accumulated amortization	302,046,000		302,046,000		274,889,000		150,245,000	136,709,000		132,678,000	119,948,000	13,544,000	13,205,000	4,057,000	3,656,000	1,474,000	1,352,000	48,000	19,000
Intangible assets, Net, Total	176,855,000		176,855,000		206,264,000
Intangible assets, Useful Life, Minimum, Years							2			4		3		4
Intangible assets, Useful Life, Maximum, Years							7			10		10		10
Intangible assets, Useful Life, Years																10		3
Amortization of intangible assets	13,700,000	12,600,000	27,700,000	25,300,000
Impairment of finite-lived intangible assets			0	0
Decrease in fair value of intangible assets						$ 300,000			$ 400,000