Net Earnings Per Common Unitholders' Interest Net Earnings (Loss) Per Common Unitholders' Interest (Earnings Distribution Allocation) (Details)	9 Months Ended
	Apr. 30, 2018 $ / shares
Upper Range [Member] | Minimum [Member]
Earnings Per Share, Basic, Distributed	$ 0.83
Upper Range [Member] | Common Stock [Member]
Allocated Distribution	51.50%
Upper Range [Member] | General Partner [Member]
Allocated Distribution	48.50%
Middle Range [Member] | Minimum [Member]
Earnings Per Share, Basic, Distributed	$ 0.64
Middle Range [Member] | Maximum [Member]
Earnings Per Share, Basic, Distributed	$ 0.82
Middle Range [Member] | Common Stock [Member]
Allocated Distribution	76.80%
Middle Range [Member] | General Partner [Member]
Allocated Distribution	23.20%
Lower Range [Member] | Minimum [Member]
Earnings Per Share, Basic, Distributed	$ 0.56
Lower Range [Member] | Maximum [Member]
Earnings Per Share, Basic, Distributed	$ 0.63
Lower Range [Member] | Common Stock [Member]
Allocated Distribution	86.90%
Lower Range [Member] | General Partner [Member]
Allocated Distribution	13.10%