Fair Values (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014	Apr. 30, 2013	Jul. 31, 2013
Debt Instrument [Line Items]
Aggregate carrying amount of equity method investments	$ 20,100,000		$ 20,100,000		$ 18,800,000
Impairment charges	0	0	0	0
Long-Term Debt [Member]
Debt Instrument [Line Items]
Fair value of debt	237,100,000		237,100,000
Debt carrying amount	225,000,000		225,000,000
Short-Term Debt [Member]
Debt Instrument [Line Items]
Fair value of debt	16,100,000		16,100,000
Debt carrying amount	$ 16,100,000		$ 16,100,000