Income taxes (Tables)

9 Months Ended

Sep. 30, 2017

Income Tax Disclosure [Abstract]

Tax Provisions before Discrete Items Reconciled to Recorded Benefits for Income Taxes

Our tax provisions before discrete items are reconciled to our recorded benefits for income taxes during the three and nine months ended September 30, 2017 and 2016 as follows (in millions):

	Three months ended September 30,						Nine months ended September 30,
	2017			2016			2017			2016
Provision for income taxes before discrete items	$	1.9		$	3.3		$	4.5		$	6.1
Interest related to unrecognized tax benefits		—			—			0.1			0.3
Reassessment of taxes upon filing tax returns		0.3			(0.2	)		0.4			(0.2	)
Provision (benefit) related to stock based compensation, including ESPP dispositions		0.4			(1.4	)		(1.9	)		(1.7	)
Benefit from reassessment of taxes upon foreign statutory tax rate change		—			—			(0.5	)		—
Benefit from reversals of uncertain tax positions due to statute of limitation expirations		(1.8	)		(13.5	)		(1.8	)		(13.5	)
Benefit from income taxes	$	0.8		$	(11.8	)	$	0.8		$	(9.0	)