Investments - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Schedule of Investments [Abstract]
Realized gain (loss) on marketable securities	$ 0.2	$ 4.5	$ 2.0	$ 4.2

Amount of realized gain (loss) on investment in debt and equity securities.

No definition available.

Name:	us-gaap_DebtAndEquitySecuritiesRealizedGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration