Fair Value Measurements - Fair Value of Debt (Details) - Convertible Notes - USD ($) $ in Millions	Sep. 30, 2023	Jul. 01, 2023	Mar. 06, 2023	Mar. 03, 2017
Debt details
Long-term Debt	$ 659.5	$ 700.1
3.75% Senior Convertible Notes
Debt details
Stated interest rate	3.75%
Long-term Debt	$ 325.7	341.8
1.625% Senior Convertible Notes
Debt details
Stated interest rate	1.625%		1.625%
Long-term Debt	$ 239.1	262.7
1.00% Senior Convertible Notes
Debt details
Stated interest rate	1.00%			1.00%
Long-term Debt	$ 94.7	95.6
Level 1
Debt details
Long-term Debt	0.0	0.0
Level 1 | 3.75% Senior Convertible Notes
Debt details
Long-term Debt	0.0	0.0
Level 1 | 1.625% Senior Convertible Notes
Debt details
Long-term Debt	0.0	0.0
Level 1 | 1.00% Senior Convertible Notes
Debt details
Long-term Debt	0.0	0.0
Level 2
Debt details
Long-term Debt	659.5	700.1
Level 2 | 3.75% Senior Convertible Notes
Debt details
Long-term Debt	325.7	341.8
Level 2 | 1.625% Senior Convertible Notes
Debt details
Long-term Debt	239.1	262.7
Level 2 | 1.00% Senior Convertible Notes
Debt details
Long-term Debt	94.7	95.6
Level 3
Debt details
Long-term Debt	0.0	0.0
Level 3 | 3.75% Senior Convertible Notes
Debt details
Long-term Debt	0.0	0.0
Level 3 | 1.625% Senior Convertible Notes
Debt details
Long-term Debt	0.0	0.0
Level 3 | 1.00% Senior Convertible Notes
Debt details
Long-term Debt	$ 0.0	$ 0.0