Fair Value Measurement - Carrying Value and Estimated Fair Value (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term borrowings	$ 370.1	$ 386.7
Credit Facility, net of original discount on borrowings and deferred financing costs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term borrowings	351.0	371.2
Credit Facility, net of original discount on borrowings and deferred financing costs | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term borrowings	351.0	371.2
Credit Facility, net of original discount on borrowings and deferred financing costs | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term borrowings	351.0	371.2
Other obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term borrowings	19.1	15.5
Other obligations | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term borrowings	19.1	15.4
Other obligations | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term borrowings	$ 19.1	$ 15.4