Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions		1 Months Ended				3 Months Ended			84 Months Ended	94 Months Ended
		Jul. 31, 2020	Jun. 30, 2020	May 31, 2020	Apr. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Apr. 30, 2020
Repurchase Plan
Subsequent Event [Line Items]
Company's common units repurchased and retired			625	106	424	1,155	782	1,281	13,340	12,800
Average price paid per unit	[1]		$ 8.45	$ 8.12	$ 7.71	$ 8.15	$ 8.33	$ 9.42	$ 8.08
Subsequent Event | Repurchase Plan
Subsequent Event [Line Items]
Company's common units repurchased and retired		725
Average price paid per unit	[1]	$ 8.97
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		$ 5.8
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		Aug. 04, 2020
Dividend record date		Jul. 27, 2020
Subsequent Event | Customer List and Assets of Heating Oil Dealer
Subsequent Event [Line Items]
Aggregate purchase price partnership acquired		$ 2.3
Aggregate purchase price allocation, intangible assets		1.9
Aggregate purchase price allocation, fixed assets		0.5
Gross purchase price increased (reduced) by working capital credits		$ (0.1)

[1] Amount includes repurchase costs.