Other Intangible Assets, net (Tables)

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

Components of Intangible Assets, Net

The components of other intangible assets, net, as of December 31, 2023 and 2022, were as follows:

			December 31,
			2023							2022
	Weighted
	Average		Intangible					Intangible		Intangible					Intangible
	Life		Assets,		Accumulated			Assets,		Assets,		Accumulated			Assets,
(millions)	(Years)		Gross		Amortization			Net		Gross		Amortization			Net
Management contract rights		5.6	$	81.0	$	(58.0	)	$	23.0	$	81.0	$	(52.9	)	$	28.1
Proprietary know how		6.1		24.1		(6.2	)		17.9		21.7		(2.7	)		19.0
Customer relationships		7.8		25.1		(8.9	)		16.2		24.8		(6.6	)		18.2
Trade names and trademarks		12.5		3.0		(1.2	)		1.8		2.8		(0.7	)		2.1
Covenant not to compete		3.7		2.9		(2.1	)		0.8		2.9		(1.4	)		1.5
Other intangible assets, net		6.5	$	136.1	$	(76.4	)	$	59.7	$	133.2	$	(64.3	)	$	68.9

Summary of Amortization of Other Intangible Assets

Amortization expense related to other intangible assets during the years ended December 31, 2023, 2022 and 2021, which was included in Depreciation and amortization within the Consolidated Statements of Income, was as follows:

	Year Ended December 31,
(millions)	2023		2022		2021
Amortization expense	$	12.0	$	9.9	$	8.7

Schedule of Expected Future Amortization of Other Intangible Assets

The expected future amortization of other intangible assets as of December 31, 2023 was as follows:

(millions)	Intangible asset amortization
2024	$	11.6
2025		10.5
2026		10.0
2027		6.9
2028		6.6
2029 and thereafter		14.1
Total	$	59.7