Marketable Investment Securities - Narrative (Details) $ in Millions	Mar. 31, 2020 USD ($)
Investments, Debt and Equity Securities [Abstract]
Available-for-sale securities with contractual maturities of one year of less	$ 705.7
Available-for-sale securities with contractual maturity of greater than one year	$ 44.5

Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next rolling fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

No definition available.

Name:	us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant