Income Taxes - Summary of Components of Deferred and Other Tax Assets and Liabilities (Parenthetical) (Detail) - Medallion Chicago [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Income Tax Rate Reconciliation [Line Items]
Net operating loss carryforwards	$ 101,627
Net operating loss carryforwards expiration period	expire at various dates between December 31, 2026 and December 31, 2035
Net operating loss carryforwards	$ 26,007
December 31, 2026 To December 31, 2035 [Member]
Income Tax Rate Reconciliation [Line Items]
Net operating loss carryforwards	$ 1,712