Stockholders' Equity - Additional Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Jul. 31, 2014
Stock Based Compensation And Stockholders Equity [Line Items]
Stock-based compensation	$ 1,565	$ 1,376
Withholding taxes payable	45,244		43,888
Dividends declared and paid	14,412
Regular Dividend
Stock Based Compensation And Stockholders Equity [Line Items]
Dividends declared and paid per common share	$ 0.27
Dividends declared and paid	14,412
Discontinued Operations
Stock Based Compensation And Stockholders Equity [Line Items]
Total compensation expenses	0	480
Restricted Stock
Stock Based Compensation And Stockholders Equity [Line Items]
Withholding taxes payable	$ 1,562