Long-Term Debt - Fair Value of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument, Redemption [Line Items]
Estimated fair value debt	$ 1,852.8	$ 1,787.6
Revolving Credit Facility
Debt Instrument, Redemption [Line Items]
Estimated fair value debt	30.0	37.0
Senior Notes
Debt Instrument, Redemption [Line Items]
Estimated fair value debt	443.4	418.6
Term Loan B Facility
Debt Instrument, Redemption [Line Items]
Estimated fair value debt	$ 1,379.4	$ 1,332.0