Summary of Significant Accounting Policies - Property and Equipment, Estimated Useful Lives (Detail)	12 Months Ended
	Dec. 31, 2019
Office equipment
Finite-Lived Intangible Assets [Line Items]
Property and equipment useful life	5 years
Automobiles
Finite-Lived Intangible Assets [Line Items]
Property and equipment useful life	5 years
Furniture and fixtures | Minimum
Finite-Lived Intangible Assets [Line Items]
Property and equipment useful life	5 years
Furniture and fixtures | Maximum
Finite-Lived Intangible Assets [Line Items]
Property and equipment useful life	7 years
Leasehold improvements | Maximum
Finite-Lived Intangible Assets [Line Items]
Property and equipment useful life	10 years