Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Effective Tax Rate Reconciliation
Income tax expense at U.S. statutory rate	$ 12.2	$ 20.8	$ 15.6
State income taxes, net of federal tax benefit	3.1	1.5	3.1
Foreign withholding taxes	6.3	0.2	1.6
U.S. taxation of international operations	18.7	1.4	(0.3)
Effective tax rate differential of earnings outside of United States	2.8	1.7	1.8
Change in valuation allowance	(2.0)	(11.6)	(5.9)
Research & experimentation	(2.0)	(2.9)	(1.0)
Provision to return	0.8	5.0	0.3
Non-deductible items	0.1	0.4	2.4
Change in uncertain tax positions	2.0	(0.3)	(0.2)
Share-based compensation	0.1	(1.1)	(4.1)
Capital (loss)	(40.5)	0.0	0.0
Unremitted earnings not permanently reinvested	0.9	0.0	0.0
Other items	0.5	0.8	0.2
Income tax expense, net	$ 3.0	$ 15.9	$ 13.5