Income Taxes - Components of Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Oct. 01, 2017	Jun. 25, 2017	Mar. 26, 2017	Dec. 25, 2016	Sep. 25, 2016	Jun. 26, 2016	Mar. 27, 2016	Dec. 31, 2017	Dec. 25, 2016	Dec. 27, 2015
Components of income (loss) from continuing operations before income taxes
Domestic									$ (54.2)	$ (61.8)	$ (54.2)
Foreign									3.4	9.5	9.6
Loss from continuing operations before income taxes									(50.8)	(52.3)	(44.6)
Federal income taxes:
Current									(0.7)	(0.5)	(15.7)
Deferred									(9.0)	4.0	1.4
Total Federal									(9.7)	3.5	(14.3)
State and local income taxes
Current									0.7	2.3	0.8
Deferred									(0.7)	0.7	0.0
Total State and local									0.0	3.0	0.8
Foreign income taxes:
Current									2.0	1.5	1.2
Deferred									(0.5)	0.1	0.9
Total Foreign									1.5	1.6	2.1
Total	$ (11.7)	$ 0.2	$ 1.8	$ 1.5	$ 0.8	$ 1.9	$ 1.8	$ 3.6	$ (8.2)	$ 8.1	$ (11.4)