Debt and Credit Arrangements - Summary of Outstanding Borrowings (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Jun. 14, 2019	Nov. 06, 2017
Debt Instrument
Total debt, net of unamortized discount and debt issuance costs	$ 442,500,000	$ 777,300,000
Less: current maturities	220,900,000	16,300,000
Long-term debt	221,600,000	761,000,000.0
Current convertible notes	220,900,000	0
Convertible Notes, due 2024 | Convertible Debt
Debt Instrument
Unamortized debt issuance costs	(3,100,000)	(3,800,000)
Principal amount	258,800,000	258,800,000		$ 258,800,000
Unamortized discount	(34,800,000)	(42,800,000)
Convertible notes due November 2024, net of unamortized discount and debt issuance costs	$ 220,900,000	212,200,000
Debt instrument stated interest rate (percent)	1.00%			1.00%
Revolving Credit Facility | Credit Facilities 2024
Debt Instrument
Unamortized debt issuance costs	$ (5,000,000.0)	(5,500,000)
Senior secured revolving credit facility and term loan, net of debt issuance costs	221,600,000	560,700,000
Revolving Credit Facility | Term long due June 2024
Debt Instrument
Long-term debt, gross	103,100,000	447,200,000
Unamortized debt issuance costs	$ (5,000,000.0)	(5,500,000)
Debt instrument stated interest rate (percent)	2.50%
Maximum borrowing capacity			$ 450,000,000.0
Revolving Credit Facility | Foreign facilities
Debt Instrument
Foreign facilities	$ 0	$ 4,400,000
Debt instrument weighted average interest rate (percent)		1.30%
Letter of credit outstanding	47,700,000	$ 12,600,000
Line of credit remaining borrowing amount	77,400,000	23,100,000
Revolving Credit Facility | Senior secured revolving credit facility
Debt Instrument
Long-term debt, gross	123,500,000	119,000,000.0
Unamortized debt issuance costs	$ (7,800,000)	$ (9,500,000)
Maximum borrowing capacity			$ 550,000,000.0
Debt instrument weighted average interest rate (percent)	2.10%
Letter of credit outstanding	$ 63,300,000
Line of credit remaining borrowing amount	363,200,000
Revolving Credit Facility Sub-limit - Letters of Credit | Senior secured revolving credit facility
Debt Instrument
Maximum borrowing capacity	100,000,000.0
Revolving Credit Facility Sub-limit - Discretionary Letters of Credit | Senior secured revolving credit facility
Debt Instrument
Maximum borrowing capacity	250,000,000.0
Revolving Credit Facility Sub-limit - Swingline | Senior secured revolving credit facility
Debt Instrument
Maximum borrowing capacity	$ 50,000,000.0