Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies - Narrative (Details) $ / shares in Units, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019 USD ($) $ / shares	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Sep. 30, 2018 USD ($) $ / shares	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Sep. 30, 2019 USD ($) segment $ / shares	Sep. 30, 2018 USD ($) $ / shares	Dec. 31, 2018 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of reportable segments | segment							2
Depreciation and amortization							$ 75.3	$ 76.1
Net income (loss)	$ 53.8	$ 76.4	$ 24.6	$ 15.9	$ 38.6	$ 43.4	$ 154.8	$ 97.9
Net income (loss) (in dollars per shares) | $ / shares	$ 0.80			$ 0.24			$ 2.31	$ 1.46
Adjustment to retained earnings as a result of adoption of new accounting guidance	$ 776.9						$ 776.9		$ 676.7
Adjustment to other liabilities as a result of adoption of new accounting guidance	(239.7)						(239.7)		(319.8)
Adjustment to deferred income taxes as a result of adoption of new accounting guidance	$ (505.0)						$ (505.0)		$ (529.4)