Financial Highlights - Summary of Ratios to Average Net Assets (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class A [Member]
Ratios to Average Net Assets:
Ratios to Average Net Assets, Net investment income (loss)	(8.10%)	(7.10%)	(5.60%)
Ratios to Average Net Assets, Net investment income (loss), Allocation to Special Limited Partner	0.00%	0.00%	0.00%
Ratios to Average Net Assets, Net investment income (loss) after allocation to Special Limited Partner	(8.10%)	(7.10%)	(5.60%)
Ratios to Average Net Assets, Operating expenses	8.10%	7.40%	7.10%
Ratios to Average Net Assets, Operating expenses, Allocation to Special Limited Partner	0.00%	0.00%	0.00%
Ratios to Average Net Assets, Total expenses	8.10%	7.40%	7.10%
Total return:
Total return before allocation to Special Limited Partner	2.30%	(1.60%)	(0.70%)
Total return, Allocation to Special Limited Partner	0.00%	0.00%	0.00%
Total return after allocation to Special Limited Partner	2.30%	(1.60%)	(0.70%)
Class D [Member]
Ratios to Average Net Assets:
Ratios to Average Net Assets, Net investment income (loss)	(6.80%)	(5.90%)	(4.30%)
Ratios to Average Net Assets, Net investment income (loss), Allocation to Special Limited Partner	(0.20%)	0.00%	0.00%
Ratios to Average Net Assets, Net investment income (loss) after allocation to Special Limited Partner	(7.00%)	(5.90%)	(4.30%)
Ratios to Average Net Assets, Operating expenses	6.80%	6.10%	5.80%
Ratios to Average Net Assets, Operating expenses, Allocation to Special Limited Partner	0.20%	0.00%	0.00%
Ratios to Average Net Assets, Total expenses	7.00%	6.10%	5.80%
Total return:
Total return before allocation to Special Limited Partner	3.50%	(0.40%)	0.50%
Total return, Allocation to Special Limited Partner	(0.20%)	0.00%	0.00%
Total return after allocation to Special Limited Partner	3.30%	(0.40%)	0.50%