Revenue from Contracts with Customers - Provision for Doubtful Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in the allowance for doubtful accounts
Balance at beginning of period	$ 6.7
Provision charged to expense	11.2	$ 16.8	$ 16.9
Balance at end of period	4.3	6.7
Trade accounts receivable
Change in the allowance for doubtful accounts
Balance at beginning of period	6.7	6.4
Provision charged to expense	8.3	11.6
Accounts written off, net of recoveries	(10.7)	(11.3)
Balance at end of period	4.3	6.7	$ 6.4
Non-trade accounts receivable
Change in the allowance for doubtful accounts
Accounts written off, net of recoveries	$ 0.0	$ (0.2)