The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Goodwill and Intangible Assets - Intangibles (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Intangible assets
Less: accumulated amortization	$ (0.7)	$ (0.1)
Intangible assets, net	10.8	9.2
Amortization expense	0.6	0.1	$ 0.0
Tradenames
Intangible assets
Intangible assets, gross	$ 0.1	0.1
Estimated Useful Life (years)	3 years
Customer relationships
Intangible assets
Intangible assets, gross	$ 11.4	$ 9.2
Minimum \| Customer relationships
Intangible assets
Estimated Useful Life (years)	15 years
Maximum \| Customer relationships
Intangible assets
Estimated Useful Life (years)	18 years