Annual report pursuant to Section 13 and 15(d)

Dividends (Parenthetical) (Detail)

v3.20.4
Dividends (Parenthetical) (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Supplemental Cash Flow Elements [Abstract]      
Dividends related to outstanding restricted stock units $ 256 $ 670 $ 624