Fair Values (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013	Jul. 31, 2013
Debt Instrument [Line Items]
Aggregate carrying amount of equity method investments	$ 18,200,000		$ 18,200,000		$ 18,800,000
Impairment charges	0	0	0	0
Long-Term Debt [Member]
Debt Instrument [Line Items]
Fair value of debt	111,400,000		111,400,000
Debt carrying amount	100,000,000		100,000,000
Short-Term Debt [Member]
Debt Instrument [Line Items]
Fair value of debt	16,200,000		16,200,000
Debt carrying amount	$ 16,200,000		$ 16,200,000