Stockholders' Equity - Additional Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended		3 Months Ended		6 Months Ended	1 Months Ended	6 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014 Regular Dividend	Oct. 31, 2013 Regular Dividend	Jan. 31, 2014 Regular Dividend	Nov. 30, 2013 Special Dividend	Jan. 31, 2014 Restricted Stock Units (RSUs)	Jan. 31, 2013 Restricted Stock Units (RSUs)	Jan. 31, 2014 Restricted Stock Units (RSUs) Discontinued Operations	Jan. 31, 2013 Restricted Stock Units (RSUs) Discontinued Operations
Equity, Class of Treasury Stock [Line Items]
Total compensation expenses							$ 2,648	$ 1,312	$ 480	$ 104
Payments related to vesting of stock-based awards	1,251
Dividends declared and paid per common share			$ 0.23	$ 0.23		$ 1.00
Cash dividends	$ 24,510	$ 19,069			$ 77,800	$ 53,290