CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Document Fiscal Period Focus			Q2
Net (loss) earnings	$ (19.5)	$ 5.9	$ (28.6)	$ 3.2
Foreign currency translation	3.4	(2.5)	(4.1)	1.5
Employee benefit plans:
Amortization or settlement of actuarial losses and prior service costs	0.3	0.2		0.3
Net change in employee benefit plans	0.3	0.2	0.2	0.3
Changes in fair value of cash flow hedges:
Unrealized net gains (losses) arising during period	0.3	(0.4)	(0.9)	0.2
Net losses reclassified into earnings	0.3	0.0	0.4	0.1
Total cash flow hedges	0.6	(0.4)	(0.5)	0.3
Other comprehensive earnings (loss), net of tax	4.3	(2.7)	(4.4)	2.1
Other comprehensive loss, net of tax			(4.4)	2.1
Comprehensive (loss) earnings	(15.2)	3.2	(33.0)	5.3
Stockholders' Equity Attributable to Parent	1,243.8	1,227.2	1,243.8	1,227.2
Net (loss) earnings	(19.5)	5.9	(28.6)	3.2
Other comprehensive loss, net of tax			(4.4)	2.1
Stock-based compensation expense	4.1	7.3	7.6	14.0
Common stock issued for exercise of stock options and other	1.3	0.9	1.7	1.8
Tax on restricted stock unit vesting	(0.2)	(0.7)	(6.0)	(5.5)
Treasury Stock, Value, Acquired, Cost Method			(15.0)
Common Stock
Stockholders' Equity Attributable to Parent	0.9	0.9	0.9	0.9
Additional Paid-In Capital
Stockholders' Equity Attributable to Parent	1,578.0	1,556.2	1,578.0	1,556.2
Stock-based compensation expense	4.1	7.3	7.6	14.0
Common stock issued for exercise of stock options and other	1.3	0.9	1.7	1.8
Tax on restricted stock unit vesting	(0.2)	(0.7)	(6.0)	(5.5)
Accumulated Deficit
Statement of Comprehensive Income [Abstract]
Net (loss) earnings	(19.5)	5.9
Stockholders' Equity Attributable to Parent	(203.7)	(221.0)	(203.7)	(221.0)
Net (loss) earnings	(19.5)	5.9
Accumulated Other Comprehensive Loss
Changes in fair value of cash flow hedges:
Other comprehensive earnings (loss), net of tax	4.3
Other comprehensive loss, net of tax	4.3	(2.7)	(4.4)	2.1
Stockholders' Equity Attributable to Parent	(116.4)	(108.9)	(116.4)	(108.9)
Other comprehensive loss, net of tax	4.3	$ (2.7)	(4.4)	$ 2.1
Treasury Stock
Stockholders' Equity Attributable to Parent	$ (15.0)		(15.0)
Treasury Stock, Value, Acquired, Cost Method			$ (15.0)