Acquisitions and Divestitures - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended		6 Months Ended			1 Months Ended	3 Months Ended	1 Months Ended	3 Months Ended	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2013	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012	Dec. 28, 2012	Aug. 31, 2012 Brady Medical [Member]	Oct. 31, 2012 Brady Medical [Member]	Oct. 31, 2012 Varitronics [Member]	Oct. 31, 2012 Varitronics [Member]	Jan. 31, 2013 Precision Dynamics Corporation [Member]	Jan. 31, 2013 Precision Dynamics Corporation [Member]	Jan. 31, 2012 Precision Dynamics Corporation [Member]	Jan. 31, 2013 Precision Dynamics Corporation [Member]	Jan. 31, 2012 Precision Dynamics Corporation [Member]	Jan. 31, 2013 Finite-lived customer relationships [Member]	Jan. 31, 2013 Trademarks [Member]
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]
Proceeds from sale of operations				$ 10,178	$ 0		$ 3,378		$ 8,410
Cash							3,018
Non-cash consideration							360
Loss (gain) on sales of businesses				(3,138)	0			(3,675)		237
Proceeds from cash distribution									7,160
Proceeds in the form of a promissory note									1,250
Net sales		324,182	320,584	661,828	670,092						16,068
Net (loss) income, as reported		(8,684)	(89,954)	18,504	(57,222)						(1,239)
Assets, fair value adjustment						16,788					1,530	1,530	1,530	1,530	1,530
Proceeds from borrowing on notes payable		220,000		220,000	0
Repayment of borrowing on notes payable				112,472	0
Expected completion of valuation	12
Customer relationships						101,500
Finite-Lived Intangible Asset, Useful Life																10 years	3 years
Finite-Lived Trade Names, Gross						6,800
Goodwill	189,942	189,942	0	189,942	0	189,942
Business Combination, Acquisition Related Costs												3,600	3,600	3,600	3,600
Interest Expense		4,406	4,933	8,569	9,980							320	357	529	720
Income tax expense (benefit)		30,625	8,635	44,107	19,744							564	(71)	(135)	(827)
Amortization of Intangible Assets		$ 5,015	$ 4,075	$ 9,162	$ 8,155							$ 3,104		$ 6,208