Consolidated Statements of Stockholders' (Deficit) Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Net Parent Investment	Accumulated Other Comprehensive Loss
Beginning balance at Jan. 01, 2017	$ 547.8	$ 0.0	$ 0.0	$ 0.0	$ 566.2	$ (18.4)
Beginning balance (in shares) at Jan. 01, 2017		0.0
Increase (Decrease) in Stockholders' Equity
Net income	161.4				161.4
Foreign currency translation adjustments, net of tax	7.1					7.1
Stock-based compensation expense	3.8				3.8
Net transfer to parent and affiliates	(148.8)				(148.8)
Ending balance at Dec. 31, 2017	571.3	$ 0.0	0.0	0.0	582.6	(11.3)
Ending balance (in shares) at Dec. 31, 2017		0.0
Increase (Decrease) in Stockholders' Equity
Net income	183.7				183.7
Foreign currency translation adjustments, net of tax	(1.7)					(1.7)
Stock-based compensation expense	3.8				3.8
Net transfer to parent and affiliates	(190.9)				(190.9)
Ending balance at Dec. 30, 2018	$ 563.2	$ 0.0	0.0	0.0	576.2	(13.0)
Ending balance (in shares) at Dec. 30, 2018	0.0	0.0
Increase (Decrease) in Stockholders' Equity
Net income	$ 193.2			87.4	105.8
Foreign currency translation adjustments, net of tax	(1.9)					(1.9)
Stock-based compensation expense	4.7		2.8		1.9
Exercise of stock options	1.6		1.6
Exercise of stock options (in shares)		0.2
Withholding taxes on stock-based awards	(0.9)		(0.9)
Reclassification of net parent investment to common stock and additional paid-in capital		$ 1.3		(214.5)	213.2
Reclassification of net parent investment to common stock and additional paid-in capital (in shares)		133.4
Dividend paid to KAR	(1,278.0)				(1,278.0)
Net transfer to parent and affiliates	379.8				379.8
Ending balance at Dec. 29, 2019	$ (137.2)	$ 1.3	$ 3.5	$ (127.1)	$ 0.0	$ (14.9)
Ending balance (in shares) at Dec. 29, 2019	133.6	133.6