Transactions with Major Customers and Concentration of Credit Risk - Schedule of Revenues from Third Party Customers (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Concentration Risk [Line Items]
Total revenue	$ 126.8	$ 121.8	$ 112.4	$ 109.1	$ 115.1	$ 107.7	$ 112.9	$ 117.2	$ 470.1	$ 452.9	[1]	$ 485.5	[1]
Customer C
Concentration Risk [Line Items]
Total revenue									$ 70.3	$ 72.9		$ 85.7

[1] The financial information presented has been retrospectively adjusted for acquisitions of businesses under common control.