Quarterly report pursuant to Section 13 or 15(d)

Equity - Class A Common Stock (Detail)

v3.19.1
Equity - Class A Common Stock (Detail) - Class A Common Stock - shares
3 Months Ended
Mar. 31, 2019
Dec. 31, 2018
Mar. 31, 2018
Dec. 31, 2017
Class Of Stock [Line Items]        
Common stock, shares outstanding 8,535,170 8,518,096 8,259,000 8,142,000
Issuance of Class A common stock upon conversion of Class B units to Class A common stock 17,074      
Common stock conversion date Mar. 31, 2019