Schedule of Investments (Unaudited) - Futures Contracts (Parenthetical) - Contract	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
COMEX Gold (1,761 contracts, settlement date August 29, 2016) [Member]
Schedule Of Investments [Line Items]
Open Future Contracts Written, Number of Contracts	1,761
Futures Contract Indexed to Issuer's Equity, Settlement Date or Dates	Aug. 29, 2016
COMEX Gold (1,307 contracts, settlement date August 29, 2016) [Member] | Total Commodity Futures Contracts Purchased [Member]
Schedule Of Investments [Line Items]
Open Future Contracts Written, Number of Contracts		1,307
Futures Contract Indexed to Issuer's Equity, Settlement Date or Dates		Aug. 29, 2016