Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions		1 Months Ended				3 Months Ended		98 Months Ended	99 Months Ended
		Jan. 31, 2021	Dec. 31, 2020	Nov. 30, 2020	Oct. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Aug. 31, 2020	Sep. 30, 2020
Repurchase Plan
Subsequent Event [Line Items]
Company's common units repurchased and retired			730	1,553	308		2,591	14,400	17,697
Average price paid per unit	[1]		$ 9.63	$ 9.83	$ 9.64		$ 9.75		$ 8.26
Common Stock Repurchase Under Private Transactions
Subsequent Event [Line Items]
Company's common units repurchased and retired						400
Subsequent Event | Repurchase Plan
Subsequent Event [Line Items]
Company's common units repurchased and retired		429
Average price paid per unit	[1]	$ 9.65
Subsequent Event | Common Stock Repurchase Under Private Transactions
Subsequent Event [Line Items]
Company's common units repurchased and retired		100
Subsequent Event | Dividend Declared
Subsequent Event [Line Items]
Distribution declared		$ 0.1325
Partners capital projected distribution amount on annualized basis		0.53
Minimum dividend distribution per unit		$ 0.0675
Amount to paid to common unit holders		$ 5.4
Amount to paid to the General Partner		0.2
Incentive distribution to the General Partner		0.2
Incentive distributions to management		$ 0.2
Dividend payable date		Feb. 02, 2021
Dividend record date		Jan. 25, 2021

[1] Amount includes repurchase costs.