CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Paid-In Capital	Retained Deficit	Retained Deficit Cumulative Effect, Period of Adoption, Adjustment	Accum. Other Comprehensive Income	Common Stock In Treasury
Beginning balance at Dec. 31, 2018	$ 414.9		$ 0.5	$ 1,295.4	$ (650.1)		$ 244.9	$ (475.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	18.4				18.4
Other comprehensive income, net	(2.2)						(2.2)
Incentive plan activity	6.9			6.9
Long-term incentive compensation expense	5.3			5.3
Restricted stock and restricted stock unit vesting	(6.6)			(22.3)				15.7
Ending balance at Jun. 29, 2019	436.7		0.5	1,285.3	(631.7)		242.7	(460.1)
Beginning balance at Mar. 30, 2019	415.3		0.5	1,279.9	(650.9)		246.6	(460.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	19.2				19.2
Other comprehensive income, net	(3.9)						(3.9)
Incentive plan activity	3.5			3.5
Long-term incentive compensation expense	2.7			2.7
Restricted stock and restricted stock unit vesting	(0.1)			(0.8)				0.7
Ending balance at Jun. 29, 2019	436.7		0.5	1,285.3	(631.7)		242.7	(460.1)
Beginning balance at Dec. 31, 2019	502.4	$ (0.5)	0.5	1,302.4	(584.8)	$ (0.5)	244.3	(460.0)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	49.8				49.8
Other comprehensive income, net	(9.0)						(9.0)
Incentive plan activity	7.6			7.6
Long-term incentive compensation expense	6.1			6.1
Restricted stock and restricted stock unit vesting	(4.3)			(12.7)				8.4
Ending balance at Jun. 27, 2020	$ 552.1		0.5	1,303.4	(535.5)		235.3	(451.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Beginning balance at Mar. 28, 2020	$ 515.1		0.5	1,298.5	(562.6)		231.4	(452.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	27.1				27.1
Other comprehensive income, net	3.9						3.9
Incentive plan activity	2.9			2.9
Long-term incentive compensation expense	3.1			3.1
Restricted stock and restricted stock unit vesting	0.0			(1.1)				1.1
Ending balance at Jun. 27, 2020	$ 552.1		$ 0.5	$ 1,303.4	$ (535.5)		$ 235.3	$ (451.6)