Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	6 Months Ended
	Jan. 31, 2018	Jan. 31, 2017
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Increase to net cash provided by operating activities	$ 109.8	$ 169.5
Increase to net cash provided by financing activities	(22.6)	$ (76.7)
Accounting Standards Update 2016-09
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Increase to net cash provided by operating activities	5.2
Increase to net cash provided by financing activities	$ 5.2