Goodwill and Intangible Assets - Other Intangible Asset (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended			6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jul. 31, 2013	Jan. 31, 2014 Patents [Member]	Jul. 31, 2013 Patents [Member]	Jan. 31, 2014 Trademarks and other [Member]	Jul. 31, 2013 Trademarks and other [Member]	Jan. 31, 2014 Customer relationships [Member]	Jul. 31, 2013 Customer relationships [Member]	Jan. 31, 2014 Non-compete agreements and other [Member]	Jul. 31, 2013 Non-compete agreements and other [Member]	Jan. 31, 2014 Trademarks [Member]	Jul. 31, 2013 Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 5,047	$ 5,015
Weighted Average Amortization Period				5 years	5 years	5 years	5 years	8 years	8 years	4 years	4 years
Gross Carrying Amount	333,760		333,681	11,299	11,053	15,726	15,289	261,245	261,076	14,415	14,942	31,075	31,321
Accumulated Amortization	(186,901)		(176,830)	(9,883)	(9,597)	(9,761)	(8,398)	(153,496)	(144,620)	(13,761)	(14,215)	0	0
Net Book Value	146,859		156,851	1,416	1,456	5,965	6,891	107,749	116,456	654	727	31,075	31,321
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	19,376
Finite-Lived Intangible Assets, Amortization Expense, Year Two	18,555
Finite-Lived Intangible Assets, Amortization Expense, Year Three	16,364
Finite-Lived Intangible Assets, Amortization Expense, Year Four	13,253
Finite-Lived Intangible Assets, Amortization Expense, Year Five	$ 11,969