Intangible Assets (Details) (USD $)	3 Months Ended		6 Months Ended			6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012	Jul. 31, 2012	Jan. 31, 2013 Technologies [Member]	Jul. 31, 2012 Technologies [Member]	Jan. 31, 2013 Customer relationships [Member]	Jul. 31, 2012 Customer relationships [Member]	Jan. 31, 2013 Trademarks and other [Member]	Jul. 31, 2012 Trademarks and other [Member]
Weighted average amortization period						11 years 8 months 12 days	11 years 8 months 12 days	10 years 0 months 0 days	10 years 0 months 0 days	20 years 0 months 0 days	20 years 0 months 0 days
Gross carrying amount	$ 83,269,000		$ 83,269,000		$ 83,669,000	$ 47,494,000	$ 47,694,000	$ 29,831,000	$ 29,931,000	$ 5,944,000	$ 6,044,000
Accumulated amortization	47,600,000		47,600,000		44,836,000	31,692,000	30,321,000	13,606,000	12,231,000	2,302,000	2,284,000
Net carrying amount	35,669,000		35,669,000		38,833,000	15,802,000	17,373,000	16,225,000	17,700,000	3,642,000	3,760,000
Amortization of intangibles	1,582,000	1,692,000	3,164,000	3,411,000
Amortization expense - year one	6,327,000		6,327,000
Amortization expense - year two	6,285,000		6,285,000
Amortization expense - year three	6,211,000		6,211,000
Amortization expense - year four	4,962,000		4,962,000
Amortization expense - year five	$ 4,782,000		$ 4,782,000