Stockholders' Equity - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	6 Months Ended		3 Months Ended		6 Months Ended		1 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended	1 Months Ended
	Jan. 31, 2013	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013 Regular Dividend	Oct. 31, 2012 Regular Dividend	Jan. 31, 2013 Regular Dividend	Jan. 31, 2012 Regular Dividend	Dec. 31, 2012 Special Dividend	Jan. 31, 2013 Special Dividend	Jan. 31, 2012 Special Dividend	Jan. 31, 2013 Cashless Exercise	Jan. 31, 2013 Cashless Exercise	Jan. 20, 2012 Catterton Repurchase Agreements	Jan. 18, 2012 Catterton Repurchase Agreements	Aug. 31, 2011 August 2011 Repurchase Agreement	Jan. 20, 2012 January 2012 Repurchase Agreement	Jan. 18, 2012 January 2012 Repurchase Agreement
Equity, Class of Treasury Stock [Line Items]
Common stock purchased, shares													1,000,000		1,000,000	1,000,000
Common stock price per share													$ 28.50		$ 20.00	$ 28.50
Aggregate purchase price of common stock			$ 77,000										$ 28,500		$ 20,000	$ 28,500
Closing price of common stock														$ 29.34	$ 20.62		$ 29.34
Percentage of issued and outstanding common stock prior to repurchase													1.80%		1.80%	1.80%
Non-cash compensation expense		1,312	323
Stock option exercised	328,479	352,479									314,000	314,000
Stock option value exercised	8,821	9,513
Share issued during period											63,464	63,464
Tax withholding paid on behalf Of employees	2,009	2,009
Cash dividends		$ 98,594				$ 19,069	$ 16,454	$ 79,525	$ 79,525
Dividends declared and paid per common share				$ 0.18	$ 0.18			$ 1.50