Net Income per Common Share - Reconciliation of Numerator and Denominator of Basic and Diluted Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Oct. 31, 2014	Oct. 31, 2013
Earnings Per Share [Line Items]
Earnings from continuing operations	$ 15,499	$ 18,134
Denominator for basic earnings (loss) from continuing operations per share for both Class A and Class B	51,251	52,071
Plus: Effect of dilutive stock options	62	348
Denominator for diluted net income per share for both Class A and Class B	51,313	52,419
Class A nonvoting common stock
Earnings Per Share [Line Items]
Earnings from continuing operations	15,499	18,089
Earnings from continuing operations per basic share	$ 0.30	$ 0.35
Earnings from continuing operations per diluted share	$ 0.30	$ 0.35
(Loss) earnings from discontinued operations per basic share	$ (0.03)	$ 0.11
(Loss) earnings from discontinued operations per diluted share	$ (0.04)	$ 0.11
Net earnings per share, basic	$ 0.27	$ 0.46
Net earnings per share, diluted	$ 0.26	$ 0.46
Class B voting common stock
Earnings Per Share [Line Items]
Earnings from continuing operations	14,704	17,270
Earnings from continuing operations per basic share	$ 0.29	$ 0.33
Earnings from continuing operations per diluted share	$ 0.29	$ 0.33
(Loss) earnings from discontinued operations per basic share	$ (0.04)	$ 0.11
(Loss) earnings from discontinued operations per diluted share	$ (0.04)	$ 0.11
Net earnings per share, basic	$ 0.25	$ 0.44
Net earnings per share, diluted	$ 0.25	$ 0.44
Restricted Stock Dividends [Member]
Earnings Per Share [Line Items]
Payments of Ordinary Dividends, Common Stock	0	45
Preferential Dividends on Class A Nonvoting Common Stock [Member]
Earnings Per Share [Line Items]
Payments of Ordinary Dividends, Common Stock	794	813
Preferential Dividends on Dilutive Shares [Member]
Earnings Per Share [Line Items]
Payments of Ordinary Dividends, Common Stock	$ 1	$ 6