Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Contingent Consideration

hanges to the contingent consideration during the years ended December 31, 2023 and 2022 were as follows:

(millions)	2023		2022
Balance, beginning of year	$	4.1	$	—
Acquisitions		—		4.0
Additions		1.0		—
Changes in fair value		0.4		0.1
Balance, end of year	$	5.5	$	4.1

Schedule of Measurement Date, Net Book Value and Related Impairment Charges for Assets

For those assets and asset groups for which impairment was recorded, the fair value as of the measurement date, net book value as of December 31, 2022 and 2021, and the related impairment charges during the years ended December 31, 2022 and 2021, were as follows:

	Year ended December 31, 2022					As of December 31, 2022
		As of Measurement Date
(millions)	Measurement Date	Impairment Charge		Fair Value Measurement (Level 3)		Net Book Value of Assets Assessed for Impairment
ROU assets	December 31, 2022	$	3.7	$	4.7
Total of ROU assets impaired		$	3.7	$	4.7	$	4.7
	Year ended December 31, 2021					As of December 31, 2021
		As of Measurement Date
(millions)	Measurement Date	Impairment Charge		Fair Value Measurement (Level 3)		Net Book Value of Assets Assessed for Impairment
ROU assets	March 31, 2021	$	0.1	$	—
ROU assets	September 30, 2021		3.5		2.0
Total of ROU assets impaired		$	3.6	$	2.0	$	1.9