Other Intangible Assets, net (Tables)

9 Months Ended

Sep. 30, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Summary of intangible assets, net

The following presents a summary of other intangible assets, net:

		September 30, 2019 (unaudited)							December 31, 2018
(millions)	Weighted Average Life (Years)	Acquired Intangible Assets, Gross (1)		Accumulated Amortization			Acquired Intangible Assets, Net		Acquired Intangible Assets, Gross (1)		Accumulated Amortization			Acquired Intangible Assets, Net
Covenant not to compete	4.2	$	1.6	$	(0.3	)	$	1.3	$	1.6	$	—		$	1.6
Trade names and trademarks	4.2	5.6		(0.9		)	4.7		6.3		(0.7		)	5.6
Proprietary know how	4.9	10.4		(1.5		)	8.9		11.0		(0.8		)	10.2
Management contract rights	9.3	81.0		(36.1		)	44.9		81.0		(32.2		)	48.8
Customer relationships	14.2	100.4		(5.6		)	94.8		100.4		(0.6		)	99.8
Acquired intangible assets, net (2)	11.8	$	199.0	$	(44.4	)	$	154.6	$	200.3	$	(34.3	)	$	166.0

(1)  Excludes the original cost and accumulated amortization of fully amortized intangible assets.

(2)  Intangible assets have estimated remaining lives between four and fifteen years.

Summary of amortization of intangible assets

The table below shows the amortization expense related to intangible assets for the three and nine months ended September 30, 2019 and September 30, 2018:

	Three Months Ended				Nine Months Ended
(millions) (unaudited)	September 30, 2019		September 30, 2018		September 30, 2019		September 30, 2018
Amortization expense related to other intangible assets included in depreciation and amortization	$	3.8	$	1.3	$	11.4	$	4.0