Condensed Schedule Of Investments (U.S. Treasury Notes) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Summary of Investment Holdings [Line Items]
Fair Value as a % of Partners' Capital	0.52%	(0.06%)
U.S. Treasury notes, 1.375%, 02/15/2020 [Member]
Summary of Investment Holdings [Line Items]
Face Amount		$ 47,270,000
Fair Value as a % of Partners' Capital		30.50%
Fair Value		$ 47,258,921
U.S. Treasury notes, 1.500%, 05/15/2020 [Member]
Summary of Investment Holdings [Line Items]
Face Amount		$ 39,370,000
Fair Value as a % of Partners' Capital		25.41%
Fair Value		$ 39,359,235
U.S. Treasury notes, 1.500%, 08/15/2020 [Member]
Summary of Investment Holdings [Line Items]
Face Amount	$ 37,470,000	$ 46,970,000
Fair Value as a % of Partners' Capital	29.65%	30.30%
Fair Value	$ 37,535,866	$ 46,942,479
U.S. Treasury notes, 1.750%, 11/15/2020 [Member]
Summary of Investment Holdings [Line Items]
Face Amount	$ 37,270,000
Fair Value as a % of Partners' Capital	29.61%
Fair Value	$ 37,492,746
U.S. Treasury notes, 2.250%, 02/15/2021 [Member]
Summary of Investment Holdings [Line Items]
Face Amount	$ 8,070,000
Fair Value as a % of Partners' Capital	6.46%
Fair Value	$ 8,175,446
U.S. Treasury notes, 2.625%, 05/15/2021 [Member]
Summary of Investment Holdings [Line Items]
Face Amount	$ 28,400,000
Fair Value as a % of Partners' Capital	22.91%
Fair Value	$ 29,009,602
U.S. Treasury Notes [Member]
Summary of Investment Holdings [Line Items]
Fair Value as a % of Partners' Capital	88.63%	86.21%
Fair Value	$ 112,213,660	$ 133,560,635