CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	Redeemable Noncontrolling Interest	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance, beginning of period (in shares) at Dec. 25, 2016			73,900,000
Balance, beginning of period at Dec. 25, 2016	$ 276.4		$ 0.0	$ 956.2	$ (1.7)	$ (678.1)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	7.8			7.8
Issuance of common stock for cash (in shares)			28,000,000.0
Issuance of common stock for cash	268.2			268.2
Issuance of common stock for employee stock purchase plan, options and warrants (in shares)			700,000
Issuance of common stock for employee stock purchase plan, options and warrants	3.5			3.5
Restricted stock issued and related taxes (in shares)			700,000
Restricted stock issued and related taxes	(2.0)			(2.0)
Net income (loss)	(42.7)					(42.7)
Other comprehensive income (loss), net of tax	0.3				0.3
Balance, end of period (in shares) at Dec. 31, 2017			103,300,000
Balance, end of period at Dec. 31, 2017	511.5		$ 0.0	1,233.7	(1.4)	(720.8)
Balance, beginning at Dec. 25, 2016		$ 0.0
Balance, ending at Dec. 31, 2017		0.0
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	7.2			7.2
Issuance of common stock for employee stock purchase plan, options and warrants (in shares)			400,000
Issuance of common stock for employee stock purchase plan, options and warrants	3.7			3.7
Restricted stock issued and related taxes (in shares)			100,000
Restricted stock issued and related taxes	(0.1)			(0.1)
Net income (loss)	(3.5)					(3.5)
Other comprehensive income (loss), net of tax	$ 0.7				0.7
Balance, end of period (in shares) at Dec. 30, 2018	103,766,899		103,800,000
Balance, end of period at Dec. 30, 2018	$ 519.3		$ 0.0	1,244.5	(0.7)	(724.5)
Balance, ending at Dec. 30, 2018		0.0
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	11.0			11.0
Issuance of common stock for employee stock purchase plan, options and warrants (in shares)			800,000
Issuance of common stock for employee stock purchase plan, options and warrants	4.9			4.9
Restricted stock issued and related taxes (in shares)			200,000
Restricted stock issued and related taxes	(0.9)			(0.9)
Issuance of common stock for acquisitions (in shares)			1,800,000
Issuance of common stock for acquisitions	27.0			27.0
Net income (loss)	12.5					12.5
Other comprehensive income (loss), net of tax	$ 0.3				0.3
Balance, end of period (in shares) at Dec. 29, 2019	106,635,508		106,600,000
Balance, end of period at Dec. 29, 2019	$ 574.1		$ 0.0	$ 1,286.5	$ (0.4)	$ (712.0)
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income		0.1
Changes in noncontrolling interest		14.9
Balance, ending at Dec. 29, 2019		$ 15.0