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																12 Months Ended
	Jul. 31, 2014		Apr. 30, 2014		Jan. 31, 2014		Oct. 31, 2013		Jul. 31, 2013		Apr. 30, 2013		Jan. 31, 2013		Oct. 31, 2012		Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Earnings Per Share [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$ (96,981)		$ 20,183		$ 10,517		$ 18,135		$ (175,557)		$ 21,680		$ (10,671)		$ 26,291		$ (48,146)	$ (138,257)	$ 103,493
Cash dividends on Common Stock																	40,487	39,243	38,899
Denominator for basic net income per share for both Class A and Class B																	51,866	51,330	52,453
Plus: Effect of dilutive stock options																			368
Denominator for diluted net income per share for both Class A and Class B																	51,866	51,330	52,821
Class A nonvoting common stock [Member]
Earnings Per Share [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent																	(48,238)	(138,495)	103,264
(Loss) earnings from continuing operations, per basic share	$ (1.89)	[1]	$ 0.39	[1]	$ 0.20	[1]	$ 0.35	[1]	$ (3.40)	[1]	$ 0.42	[1]	$ (0.21)	[1]	$ 0.51	[1]	$ (0.93)	$ (2.70)	$ 1.97
(Loss) earnings from continuing operations, per diluted share	$ (1.89)	[1]	$ 0.39	[1]	$ 0.20	[1]	$ 0.35	[1]	$ (3.40)	[1]	$ 0.42	[1]	$ (0.21)	[1]	$ 0.51	[1]	$ (0.93)	$ (2.70)	$ 1.95
Earnings (loss) from discontinued operations, per basic share	$ (0.26)	[1]	$ 0.08	[1]	$ 0.11	[1]	$ 0.11	[1]	$ (0.03)	[1]	$ (0.34)	[1]	$ 0.04	[1]	$ 0.02	[1]	$ 0.04	$ (0.32)	$ (2.31)
Earnings (loss) from discontinued operations, per diluted share	$ (0.26)	[1]	$ 0.08	[1]	$ 0.11	[1]	$ 0.11	[1]	$ (0.03)	[1]	$ (0.34)	[1]	$ 0.04	[1]	$ 0.02	[1]	$ 0.04	$ (0.32)	$ (2.29)
Net loss per share, basic																	$ (0.89)	$ (3.02)	$ (0.35)
Net loss per share, diluted																	$ (0.89)	$ (3.02)	$ (0.34)
Class B voting common stock [Member]
Earnings Per Share [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent																	(49,057)	(139,297)	102,441
(Loss) earnings from continuing operations, per basic share																	$ (0.95)	$ (2.71)	$ 1.95
(Loss) earnings from continuing operations, per diluted share																	$ (0.95)	$ (2.71)	$ 1.94
Earnings (loss) from discontinued operations, per basic share																	$ 0.05	$ (0.32)	$ (2.31)
Earnings (loss) from discontinued operations, per diluted share																	$ 0.05	$ (0.32)	$ (2.30)
Net loss per share, basic																	$ (0.90)	$ (3.03)	$ (0.36)
Net loss per share, diluted																	$ (0.90)	$ (3.03)	$ (0.36)
Restricted Stock [Member]
Earnings Per Share [Line Items]
Cash dividends on Common Stock																	92	238	229
Preferential Dividends on Class A Nonvoting Common Stock [Member]
Earnings Per Share [Line Items]
Cash dividends on Common Stock																	813	797	818
Preferential Dividends on Dilutive Shares [Member]
Earnings Per Share [Line Items]
Cash dividends on Common Stock																	$ 6	$ 5	$ 5

[1] *** The sum of the quarters does not equal the year-to-date total for fiscal 2014 and fiscal 2013 due to the quarterly changes inweighted-average shares outstanding.