Investment Securities - Additional Information (Details)	Sep. 30, 2021 USD ($) Security	Dec. 31, 2020 USD ($) Security
Schedule Of Available For Sale Securities [Line Items]
Number of available-for-sale investment securities in continuous unrealized loss position, less than 12 months	19	0
Number of domestic certificates of deposit held	25
Maximum
Schedule Of Available For Sale Securities [Line Items]
Accrued interest receivable on available-for-sale investment securities \| $	$ 100,000	$ 100,000

Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without an allowance for credit loss. Includes beneficial interest in securitized financial asset.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922888-210455

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant