Income taxes (Tables)

6 Months Ended

Jan. 31, 2018

Income Tax Disclosure [Abstract]

Provision for Income Taxes and Effective Tax Rate

The following table presents the provision for income taxes and our effective tax rate for the three and six months ended January 31, 2018 and 2017:

	Three Months Ended						Six Months Ended
	January 31,						January 31,
(in millions except percentages)	2018			2017			2018			2017
Provision for income taxes	$	10.1		$	2.0		$	12.6		$	2.9
Effective tax rate		61	%		21	%		51	%		23	%