Goodwill and Intangible Assets - Additional Informations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Jul. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Goodwill increased	$ 3,804
Accumulated impairment	115,688
Amortization expense of intangible assets	4,147	4,080
Projected Future amortization expense, year one			14,383
Projected Future amortization expense, year two			7,060
Projected Future amortization expense, year three			6,265
Projected Future amortization expense, year four			5,359
Projected Future amortization expense, year five			$ 2,918