Summary of Significant Accounting Policies - Schedule of Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Investments In Loans [Line Items]
Intangibles assets	$ 51,090	$ 52,536
Intellectual Property [Member]
Investments In Loans [Line Items]
Intangibles assets	18,974	20,075
Contractor Relationships [Member]
Investments In Loans [Line Items]
Intangibles assets	5,951	6,296
Race Organization [Member]
Investments In Loans [Line Items]
Intangibles assets	$ 26,165	$ 26,165

Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph ((a)(1),(b))
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274

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