Partners' Capital and Distributions - Schedule of Distributions Declared and Paid (Detail)	3 Months Ended
	Mar. 31, 2021 $ / shares
First Quarter 2020
Distribution Made To Limited Partner [Line Items]
Record Date	May 04, 2020
Distribution Date	May 14, 2020
Distribution per Class A share	$ 0.4310
Second Quarter 2020
Distribution Made To Limited Partner [Line Items]
Record Date	Aug. 06, 2020
Distribution Date	Aug. 14, 2020
Distribution per Class A share	$ 0.4363
Third Quarter 2020
Distribution Made To Limited Partner [Line Items]
Record Date	Nov. 05, 2020
Distribution Date	Nov. 13, 2020
Distribution per Class A share	$ 0.4417
Fourth Quarter 2020
Distribution Made To Limited Partner [Line Items]
Record Date	Feb. 04, 2021
Distribution Date	Feb. 12, 2021
Distribution per Class A share	$ 0.4471
First Quarter 2021
Distribution Made To Limited Partner [Line Items]
Record Date	May 03, 2021	[1]
Distribution Date	May 13, 2021	[1]
Distribution per Class A share	$ 0.4526	[1]

[1] For more information, see Note 14, Subsequent Events.