Quarterly report pursuant to Section 13 or 15(d)

Equity - Class B Common Stock (Detail)

v3.20.2
Equity - Class B Common Stock (Detail) - Class B Common Stock - shares
 1 Months Ended 3 Months Ended
Aug. 31, 2020
Jun. 30, 2020
May 31, 2020
Mar. 31, 2020
Feb. 29, 2020
Sep. 30, 2020
Jun. 30, 2020
Mar. 31, 2020
Sep. 30, 2019
Jun. 30, 2019
Mar. 31, 2019
Dec. 31, 2019
Dec. 31, 2018
Class Of Stock [Line Items]                          
Common stock conversion date 2020-08 2020-06 2020-05 2020-03 2020-02                
Issuance of Class B common stock upon vesting of restricted stock units     2020-05                    
Common stock, shares outstanding   4,852,000   4,855,000   4,827,731 4,852,000 4,855,000 5,181,000 4,833,000 4,919,000 5,031,017 4,934,000
Cancellation of Class B common stock upon conversion of Class B units to Class A common stock (24,191)   (7,355)     24,000 12,000 176,000 556,000 87,000 17,000    
Issuance of Class A and Class B common stock upon vesting of restricted stock units     9,546           663,000   2,000    
Resale And Registration Rights Agreement                          
Class Of Stock [Line Items]                          
Cancellation of Class B common stock upon conversion of Class B units to Class A common stock (24,191) (5,400) (7,355) (20,662) (155,224)