Income Tax Matters - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income tax (benefit) provision	$ (0.7)	$ 8.7	$ 10.2	$ 25.8
Effective tax rate (percent)	222.00%	26.00%	31.00%	26.00%
Effective tax rate reconciliation, increase (decrease) to the valuation allowance for certain state net operating losses	$ 0.1		$ 1.3	$ 0.6
Effective tax rate reconciliation, increase (decrease) to the valuation allowance for certain state net operating losses (percent)	22.00%		4.00%	1.00%
Effective tax rate reconciliation, change in forecasted earnings	$ (0.7)
Effective income tax rate reconciliation, change in forecasted earnings percent	211.00%
Effective income tax rate reconciliation, nondeductible expense, amount		$ 0.5	$ 1.2	$ 1.5
Effective income tax rate reconciliation, nondeductible expense, percent		2.00%	4.00%	2.00%
Effective income tax rate reconciliation, tax expense (benefit), share-based payment arrangement, amount			$ (0.7)	$ (0.6)
Effective income tax rate reconciliation, tax expense (benefit), share-based payment arrangement, percent			2.00%	1.00%
Gross unrecognized tax benefits	$ 3.9		$ 3.9		$ 4.1
Gross unrecognized tax benefits that would impact effective tax rate	$ 0.4		$ 0.4		$ 0.9