Net Earnings (Loss) Per Common Unitholders' Interest Net Earnings (Loss) Per Common Unitholders' Interest (Earnings Distribution Allocation) (Details)	12 Months Ended
	Jul. 31, 2017 $ / shares
Upper Range [Member] | Common Stock [Member]
Earnings Distribution Allocation [Line Items]
Allocated Distribution	51.50%
Upper Range [Member] | General Partner [Member]
Earnings Distribution Allocation [Line Items]
Allocated Distribution	48.50%
Middle Range [Member] | Common Stock [Member]
Earnings Distribution Allocation [Line Items]
Allocated Distribution	76.80%
Middle Range [Member] | General Partner [Member]
Earnings Distribution Allocation [Line Items]
Allocated Distribution	23.20%
Lower Range [Member] | Common Stock [Member]
Earnings Distribution Allocation [Line Items]
Allocated Distribution	86.90%
Lower Range [Member] | General Partner [Member]
Earnings Distribution Allocation [Line Items]
Allocated Distribution	13.10%
Minimum [Member] | Upper Range [Member]
Earnings Distribution Allocation [Line Items]
Earnings Per Share, Basic, Distributed	$ 0.83
Minimum [Member] | Middle Range [Member]
Earnings Distribution Allocation [Line Items]
Earnings Per Share, Basic, Distributed	0.64
Minimum [Member] | Lower Range [Member]
Earnings Distribution Allocation [Line Items]
Earnings Per Share, Basic, Distributed	0.56
Maximum [Member] | Middle Range [Member]
Earnings Distribution Allocation [Line Items]
Earnings Per Share, Basic, Distributed	0.82
Maximum [Member] | Lower Range [Member]
Earnings Distribution Allocation [Line Items]
Earnings Per Share, Basic, Distributed	$ 0.63