Acquisitions and Divestitures - Pro Forma (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014	Apr. 30, 2013
Business Acquisition [Line Items]
Net sales	$ 309,577	$ 302,483	$ 908,301	$ 847,200
Net sales, pro forma	309,577	302,483	908,301	915,625
Earnings from continuing operations, as reported	20,184	21,680	48,835	37,300
Earnings from continuing operations, pro forma	$ 20,184	$ 21,680	$ 48,835	$ 41,600
Basic earnings from continuing operations per Class A Common Share, as reported	$ 0.39	$ 0.42	$ 0.94	$ 0.72
Basic earnings from continuing operations per Class A Common Share, pro forma	$ 0.39	$ 0.42	$ 0.94	$ 0.81
Diluted earnings from continuing operations per Class A Common Share, as reported	$ 0.39	$ 0.42	$ 0.93	$ 0.72
Diluted earnings from continuing operations per Class A Common Share, pro forma	$ 0.39	$ 0.42	$ 0.93	$ 0.80