Debt - Summary of Carrying Amounts and Estimated Fair Values of Long-Term Borrowings (Details) - USD ($) $ in Millions		Jun. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term borrowings		$ 248.1	$ 277.7
Current portion of long-term borrowings and capital lease obligations		0.3	0.3
Notional Amount
Debt Instrument [Line Items]
Long-term borrowings	[1]	248.1	277.7
Fair Value
Debt Instrument [Line Items]
Long-term borrowings	[1]	$ 248.1	$ 277.7

[1] Long-term borrowings includes current portions of long-term debt and current portions of capital lease obligations of $0.3 million and $0.3 million as of June 30, 2018 and December 31, 2017, respectively.