Schedule I - Dividends from Subsidiary - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Parent Company [Member]
Dividends Payable [Line Items]
Dividends from subsidiary- return of capital, for purchase of treasury stock	$ 12,406	$ 150,000	$ 98,032