Stockholders' Equity - Additional Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended		3 Months Ended			9 Months Ended	1 Months Ended	9 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014 Regular Dividend	Jan. 31, 2014 Regular Dividend	Oct. 31, 2013 Regular Dividend	Apr. 30, 2014 Regular Dividend	Nov. 30, 2013 Special Dividend	Apr. 30, 2014 Restricted Stock Units (RSUs)	Apr. 30, 2013 Restricted Stock Units (RSUs)	Apr. 30, 2014 Restricted Stock Units (RSUs) Discontinued Operations	Apr. 30, 2013 Restricted Stock Units (RSUs) Discontinued Operations
Stock Based Compensation And Stockholders Equity [Line Items]
Total compensation expenses								$ 3,943	$ 2,051	$ 480	$ 156
Payments related to vesting of stock-based awards	1,251
Dividends declared and paid per common share			$ 0.23	$ 0.23	$ 0.23		$ 1.00
Cash dividends						90,057
Regular cash dividends paid	36,767	28,614
Special cash dividends paid	$ 53,290	$ 79,525					$ 53,290