Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 25, 2017	Jun. 26, 2016
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities from continuing operations	$ (11.3)	$ (12.4)
Investing activities:
Investment in affiliated companies	0.0	0.0
Change in restricted cash	0.2	0.0
Capital expenditures	(12.1)	(3.5)
Net cash used in investing activities from continuing operations	(11.9)	(3.5)
Financing activities:
Extinguishment of long-term debt	(64.0)	0.0
Repayment of debt	(0.5)	(0.5)
Proceeds from the issuance of common stock	81.7	0.0
Proceeds from the sale of employee stock purchase plan shares	0.6	1.0
Financing from affiliated companies	0.0	0.0
Net cash provided by financing activities from continuing operations	17.8	0.5
Net cash flows of continuing operations	(5.4)	(15.4)
Net operating cash flows of discontinued operations	(0.1)	0.1
Net investing cash flows of discontinued operations	(0.4)	4.5
Effect of exchange rate changes on cash and cash equivalents	0.1	(0.1)
Net decrease in cash and cash equivalents	(5.8)	(10.9)
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities from continuing operations	0.0	0.0
Investing activities:
Investment in affiliated companies	10.9	2.3
Change in restricted cash	0.0
Capital expenditures	0.0	0.0
Net cash used in investing activities from continuing operations	10.9	2.3
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	(10.9)	(2.3)
Net cash provided by financing activities from continuing operations	(10.9)	(2.3)
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	0.0
Net 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	(14.5)	(13.2)
Investing activities:
Investment in affiliated companies	(10.9)	(2.3)
Change in restricted cash	0.0
Capital expenditures	(0.1)	(0.5)
Net cash used in investing activities from continuing operations	(11.0)	(2.8)
Financing activities:
Extinguishment of long-term debt	(64.0)
Repayment of debt	0.0	0.0
Proceeds from the issuance of common stock	81.7
Proceeds from the sale of employee stock purchase plan shares	0.6	1.0
Financing from affiliated companies	0.0	0.0
Net cash provided by financing activities from continuing operations	18.3	1.0
Net cash flows of continuing operations	(7.2)	(15.0)
Net operating cash flows of discontinued operations	0.0	0.2
Net investing cash flows of discontinued operations	(0.4)	4.5
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0
Net decrease in cash and cash equivalents	(7.6)	(10.3)
Subsidiary Guarantors on a Combined Basis
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities from continuing operations	2.1	1.5
Investing activities:
Investment in affiliated companies	0.0	0.0
Change in restricted cash	0.2
Capital expenditures	(11.4)	(2.0)
Net cash used in investing activities from continuing operations	(11.2)	(2.0)
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	10.9	2.3
Net cash provided by financing activities from continuing operations	10.9	2.3
Net cash flows of continuing operations	1.8	1.8
Net operating cash flows of discontinued operations	(0.1)	(0.1)
Net investing cash flows of discontinued operations	0.0	0.0
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0
Net decrease in cash and cash equivalents	1.7	1.7
Non-Guarantors on a Combined Basis
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities from continuing operations	1.1	(0.7)
Investing activities:
Investment in affiliated companies	0.0	0.0
Change in restricted cash	0.0
Capital expenditures	(0.6)	(1.0)
Net cash used in investing activities from continuing operations	(0.6)	(1.0)
Financing activities:
Extinguishment of long-term debt	0.0
Repayment of debt	(0.5)	(0.5)
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	(0.5)	(0.5)
Net cash flows of continuing operations	0.0	(2.2)
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	0.1	(0.1)
Net decrease in cash and cash equivalents	$ 0.1	$ (2.3)