Acquisitions and Divestitures - Pro Forma (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013
Business Acquisition [Line Items]
Interest expense	$ (3,676)	$ (4,406)	$ (7,397)	$ (8,569)
Income tax expense	4,408	28,960	13,002	42,138
Net sales	291,194	272,702	598,724	544,717
Net sales, pro forma	291,194	299,077	598,724	613,142
Earnings (loss) from continuing operations, as reported	10,517	(10,671)	28,652	15,620
Earnings (loss) from continuing operations, pro forma	10,517	(7,275)	28,652	19,920
Basic net (loss) income per Class A Common Share, pro forma (USD per share)		$ (0.14)		$ 0.39
Diluted net (loss) income per Class A Common Share, pro forma (USD per share)		$ (0.14)		$ 0.39
Amortization of Intangible Assets			5,047	5,015
Nonvoting Common Stock [Member]
Business Acquisition [Line Items]
Earnings (loss) from continuing operations, as reported	$ 10,501	$ (10,731)	$ 28,591	$ 15,501
Earnings (loss) from continuing operations per basic share	$ 0.20	$ (0.21)	$ 0.55	$ 0.30
Basic net (loss) income per Class A Common Share, pro forma (USD per share)	$ 0.20		$ 0.55
Earnings (loss) from continuing operations per diluted share	$ 0.20	$ (0.21)	$ 0.55	$ 0.30
Diluted net (loss) income per Class A Common Share, pro forma (USD per share)	$ 0.20		$ 0.55