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	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Intangible assets
Total	$ 11.0		$ 11.0		$ 9.2
Amortization of Intangible Assets	0.2	$ 0.0	0.4	$ 0.0
Tradenames
Intangible assets
Intangible assets, gross	0.1		$ 0.1		$ 0.1
Estimated useful life			3 years		3 years
Customer relationships
Intangible assets
Intangible assets, gross	11.4		$ 11.4		$ 9.2
Less: accumulated amortization	$ (0.5)		$ (0.5)		$ (0.1)
Minimum \| Customer relationships
Intangible assets
Estimated useful life			15 years		15 years
Maximum \| Customer relationships
Intangible assets
Estimated useful life			18 years		18 years