Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Millions	9 Months Ended
	Oct. 01, 2017	Sep. 25, 2016
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities from continuing operations	$ (16.7)	$ (8.7)
Investing activities:
Cash paid for acquisitions, net of cash acquired	0.2	0.0
Investment in affiliated companies	0.0	0.0
Change in restricted cash	0.2	0.1
Capital expenditures	(18.3)	(5.1)
Net cash used in investing activities from continuing operations	(17.9)	(5.0)
Financing activities:
Extinguishment of long-term debt	(64.0)	0.0
Repayment of debt	(0.8)	(0.8)
Proceeds from the issuance of common stock	268.0	0.0
Proceeds from the sale of employee stock purchase plan shares	1.5	2.1
Financing from affiliated companies	0.0	0.0
Net cash provided by financing activities from continuing operations	204.7	1.3
Net cash flows of continuing operations	170.1	(12.4)
Net operating cash flows of discontinued operations	(0.1)	0.1
Net investing cash flows of discontinued operations	(0.5)	4.3
Effect of exchange rate changes on cash and cash equivalents	0.6	0.0
Net increase (decrease) in cash and cash equivalents	170.1	(8.0)
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities from continuing operations	0.0	0.0
Investing activities:
Cash paid for acquisitions, net of cash acquired	0.0
Investment in affiliated companies	23.0	1.0
Change in restricted cash	0.0	0.0
Capital expenditures	0.0	0.0
Net cash used in investing activities from continuing operations	23.0	1.0
Financing activities:
Extinguishment of long-term debt	0.0
Repayment of debt	0.0	0.0
Proceeds from the issuance of common stock	0.0
Proceeds from the sale of employee stock purchase plan shares	0.0	0.0
Financing from affiliated companies	(23.0)	(1.0)
Net cash provided by financing activities from continuing operations	(23.0)	(1.0)
Net cash flows of continuing operations	0.0	0.0
Net operating cash flows of discontinued operations	0.0	0.0
Net investing cash flows of discontinued operations	0.0	0.0
Effect of exchange rate changes on cash and cash equivalents	0.0
Net increase (decrease) in cash and cash equivalents	0.0	0.0
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities from continuing operations	(15.3)	(12.0)
Investing activities:
Cash paid for acquisitions, net of cash acquired	0.0
Investment in affiliated companies	(23.0)	(1.0)
Change in restricted cash	0.0	0.0
Capital expenditures	(0.8)	(0.5)
Net cash used in investing activities from continuing operations	(23.8)	(1.5)
Financing activities:
Extinguishment of long-term debt	(64.0)
Repayment of debt	0.0	0.0
Proceeds from the issuance of common stock	268.0
Proceeds from the sale of employee stock purchase plan shares	1.5	2.1
Financing from affiliated companies	0.0	0.0
Net cash provided by financing activities from continuing operations	205.5	2.1
Net cash flows of continuing operations	166.4	(11.4)
Net operating cash flows of discontinued operations	(0.1)	0.3
Net investing cash flows of discontinued operations	(0.5)	4.3
Effect of exchange rate changes on cash and cash equivalents	0.0
Net increase (decrease) in cash and cash equivalents	165.8	(6.8)
Subsidiary Guarantors on a Combined Basis
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities from continuing operations	(6.1)	5.6
Investing activities:
Cash paid for acquisitions, net of cash acquired	0.2
Investment in affiliated companies	0.0	0.0
Change in restricted cash	0.2	0.1
Capital expenditures	(16.1)	(3.2)
Net cash used in investing activities from continuing operations	(15.7)	(3.1)
Financing activities:
Extinguishment of long-term debt	0.0
Repayment of debt	0.0	0.0
Proceeds from the issuance of common stock	0.0
Proceeds from the sale of employee stock purchase plan shares	0.0	0.0
Financing from affiliated companies	23.0	1.0
Net cash provided by financing activities from continuing operations	23.0	1.0
Net cash flows of continuing operations	1.2	3.5
Net operating cash flows of discontinued operations	0.0	(0.2)
Net investing cash flows of discontinued operations	0.0	0.0
Effect of exchange rate changes on cash and cash equivalents	0.0
Net increase (decrease) in cash and cash equivalents	1.2	3.3
Non-Guarantors on a Combined Basis
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities from continuing operations	4.7	(2.3)
Investing activities:
Cash paid for acquisitions, net of cash acquired	0.0
Investment in affiliated companies	0.0	0.0
Change in restricted cash	0.0	0.0
Capital expenditures	(1.4)	(1.4)
Net cash used in investing activities from continuing operations	(1.4)	(1.4)
Financing activities:
Extinguishment of long-term debt	0.0
Repayment of debt	(0.8)	(0.8)
Proceeds from the issuance of common stock	0.0
Proceeds from the sale of employee stock purchase plan shares	0.0	0.0
Financing from affiliated companies	0.0	0.0
Net cash provided by financing activities from continuing operations	(0.8)	(0.8)
Net cash flows of continuing operations	2.5	(4.5)
Net operating cash flows of discontinued operations	0.0	0.0
Net investing cash flows of discontinued operations	0.0	0.0
Effect of exchange rate changes on cash and cash equivalents	0.6
Net increase (decrease) in cash and cash equivalents	$ 3.1	$ (4.5)