Income Taxes - Reconciliation of the Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 6,831	$ 4,718	$ 2,650
Additions attributable to state and local tax apportionment	9,486	2,113	2,068
Balance at end of year	$ 16,317	$ 6,831	$ 4,718