Acquisitions and Divestitures - Pro Forma (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012
Business Acquisition [Line Items]
Net sales	$ 324,182	$ 320,584	$ 661,828	$ 670,092
Net sales, pro forma	350,558	360,074	730,253	751,603
Net (loss) income, as reported	(8,684)	(89,954)	18,504	(57,222)
Net (loss) income, pro forma	$ (4,695)	$ (90,070)	$ 23,414	$ (60,101)
Basic net (loss) income per Class A Common Share, pro forma (USD per share)	$ (0.09)	$ (1.72)	$ 0.46	$ (1.15)
Diluted net (loss) income per Class A Common Share, pro forma (USD per share)	$ (0.09)	$ (1.72)	$ 0.45	$ (1.15)
Nonvoting Common Stock [Member]
Business Acquisition [Line Items]
Basic net (loss) income per Class A Common Share, as reported (USD per share)	$ (0.17)	$ (1.72)	$ 0.36	$ (1.09)
Diluted net (loss) income per Class A Common Share, as reported (USD per share)	$ (0.17)	$ (1.72)	$ 0.36	$ (1.09)