Investments - Additional Information (Detail) - Debt [Member] - U.S. Treasury Securities [Member]	6 Months Ended
Jun. 30, 2021
Minimum [Member]
Schedule of Investments [Line Items]
US Treasury securities maturity period	3 months
Maximum [Member]
Schedule of Investments [Line Items]
US Treasury securities maturity period	1 year

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_ScheduleOfInvestmentsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration