Common Shares and Net Income (Loss) per Common Share - Reconciliation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Numerator (in millions of U.S. dollars):
Net income (loss) from continuing operations	$ 22.3	$ 7.3	$ (136.8)	$ (12.7)
Net (loss) income from discontinued operations	(0.3)	2.8	26.3	7.5
Net income (loss)	$ 22.0	$ 10.1	$ (110.5)	$ (5.2)
Denominator (in thousands):
Weighted average common shares outstanding - basic (in shares)	160,101	134,667	153,723	135,395
Basic Earnings Per Share:
Continuing operations (in USD per share)	$ 0.14	$ 0.05	$ (0.89)	$ (0.09)
Discontinued operations (in USD per share)	0	0.02	0.17	0.05
Net income (loss) (in USD per share)	$ 0.14	$ 0.07	$ (0.72)	$ (0.04)
Denominator (in thousands):
Weighted average common shares outstanding - basic (in shares)	160,101	134,667	153,723	135,395
Weighted average common shares outstanding - diluted (in shares)	161,433	136,208	153,723	135,395
Continued operations (in USD per share)	$ 0.14	$ 0.05	$ (0.89)	$ (0.09)
Discontinued operations (in USD per share)	0	0.02	0.17	0.05
Net income (loss) (in USD per share)	$ 0.14	$ 0.07	$ (0.72)	$ (0.04)
Performance-based RSUs
Denominator (in thousands):
Dilutive effect (in shares)	132	644	0	0
Time-based RSUs
Denominator (in thousands):
Dilutive effect (in shares)	284	211	0	0
Stock Options
Denominator (in thousands):
Dilutive effect (in shares)	916	686	0	0