Leasehold Improvements, Equipment, Land and Construction in Progress, net (Tables)

12 Months Ended

Dec. 31, 2018

Property, Plant and Equipment [Abstract]

Summary of leasehold improvements, equipment, and construction in progress and related accumulated depreciation and amortization

Leasehold improvements, equipment, and construction in progress and related accumulated depreciation and amortization is as follows:

		December 31
(millions)	Ranges of Estimated Useful Life	2018			2017
Equipment	1 - 10 Years	$	41.5		$	39.6
Software	2 - 5 Years	34.7			31.9
Vehicles	1 - 10 Years	23.6			9.1
Other	3 Years	0.6			0.5
Leasehold improvements	Shorter of lease term or economic life up to 10 years	17.7			20.8
Construction in progress		4.4			2.7
		122.5			104.6
Less accumulated depreciation and amortization		(82.2		)	(77.2		)
Leasehold improvements, equipment, land and construction in progress, net		$	40.3		$	27.4

The table below shows the Company's depreciation and amortization expense related to Leasehold improvements, equipment and construction in progress for the years ended December 31, 2018, 2017 and 2016, and is included in Depreciation and amortization expense within the Consolidated Statements of Income.

	Year Ended December 31,
(millions)	2018		2017		2016
Depreciation expense	$	9.6	$	11.3	$	16.2