Debt and Credit Arrangements - Scheduled Annual Maturities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Nov. 06, 2017
Debt Instrument
Senior secured revolving credit facility and term loan, net of debt issuance costs	$ 859,600,000
Interest expense, debt	11,700,000	$ 18,100,000	$ 17,700,000
Convertible Notes, due 2024 | Convertible Debt
Debt Instrument
Principal amount	258,800,000	258,800,000		$ 258,800,000
Interest expense, debt	$ 2,600,000	$ 10,600,000	$ 10,200,000