Trading Activities - Additional Information (Detail)	3 Months Ended		6 Months Ended
Trading Activities - Additional Information (Detail)	Jun. 30, 2019 USD ($) Contract	Jun. 30, 2018 USD ($) Contract	Jun. 30, 2019 USD ($) Contract	Jun. 30, 2018 USD ($) Contract
Trading Activity, Gains and Losses, Net [Line Items]
Monthly average number of futures contracts traded	3,643		3,516
Monthly average number of metals forward contracts traded	495		428
Forward Contracts [Member] \| Currencies [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Average notional values of currency forward contracts \| $	$ 760,666,346		$ 669,368,344
CMF Campbell Master Fund L.P. [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Monthly average number of futures contracts traded		1,346		1,348
Monthly average number of metals forward contracts traded		182		156
CMF Campbell Master Fund L.P. [Member] \| Forward Contracts [Member] \| Currencies [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Average notional values of currency forward contracts \| $		$ 173,399,278		$ 161,799,446

POTOMAC FUTURES FUND LP 10-Q