Goodwill and Other Intangible Assets - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Intangible asset amortization expense	$ 2.7	$ 1.7	$ 6.1	$ 5.5
Customer contracts and relationships
Segment Reporting Information [Line Items]
Weighted-average amortization period of intangible assets			9 years 7 months 6 days
Operating contracts and licenses
Segment Reporting Information [Line Items]
Weighted-average amortization period of intangible assets			27 years 3 months 18 days
Other
Segment Reporting Information [Line Items]
Weighted-average amortization period of intangible assets			3 years 7 months 6 days