Equity Transactions (Issuance of Mandatory Convertible Preferred Stock) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2018	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Preferred stock dividends paid			$ 4.7	$ 18.7	$ 18.7
Series D Preferred Stock
Class of Stock [Line Items]
Number of shares issued (in shares)		2,875,000
Sale of stock, price per share (in dollars per share)		$ 100.00
Issuance of mandatory convertible preferred stock, net of issuance costs		$ 276.4
Shares conversion ratio	0.9405
Shares converted (in shares)	2,703,911
Liquidation preference per share (in dollars per share)			$ 100.00
Preferred stock, dividend rate			6.50%	6.50%