Statements of Changes in Shareholders' Equity and Redeemable Capital Shares (Unaudited) - USD ($)	Total	Retained Earnings [Member]	Redeemable Capital Shares [Member]
Balance, Shares at Dec. 31, 2017			1,600,000
Balance at Dec. 31, 2017			$ 210,380,158
Purchases of Shares			$ 13,369,333
Purchases of Shares, Shares			100,000
Redemption of Shares			$ (53,469,708)
Redemptions of Shares, Shares			(400,000)
Net Increase (Decrease) due to Share Transactions			$ (40,100,375)
Net Increase (Decrease) due to Share Transactions, Shares			(300,000)
Net Comprehensive Income (Loss)	$ (288,919)	$ (288,919)
Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings	288,919	288,919	$ (288,919)
Adjustment of Redeemable Capital Shares to Redemption Value			$ (3,420,663)
Balance, Shares at Jun. 30, 2018			1,300,000
Balance at Jun. 30, 2018			$ 166,570,201
Balance, Shares at Mar. 31, 2018			1,450,000
Balance at Mar. 31, 2018			$ 197,561,432
Redemption of Shares			$ (19,662,398)
Redemptions of Shares, Shares			(150,000)
Net Increase (Decrease) due to Share Transactions			$ (19,662,398)
Net Increase (Decrease) due to Share Transactions, Shares			(150,000)
Net Comprehensive Income (Loss)	(141,165)	(141,165)
Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings	$ 141,165	141,165	$ (141,165)
Adjustment of Redeemable Capital Shares to Redemption Value			$ (11,187,668)
Balance, Shares at Jun. 30, 2018			1,300,000
Balance at Jun. 30, 2018			$ 166,570,201
Balance, Shares at Dec. 31, 2018	1,100,000		1,100,000
Balance at Dec. 31, 2018	$ 135,895,374		$ 135,895,374
Purchases of Shares			$ 44,144,699
Purchases of Shares, Shares			350,000
Redemption of Shares			$ (56,390,412)
Redemptions of Shares, Shares			(450,000)
Net Increase (Decrease) due to Share Transactions			$ (12,245,713)
Net Increase (Decrease) due to Share Transactions, Shares			(100,000)
Net Comprehensive Income (Loss)	(31,785)	(31,785)
Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings	$ 31,785	31,785	$ (31,785)
Adjustment of Redeemable Capital Shares to Redemption Value			$ (193,660)
Balance, Shares at Jun. 30, 2019	1,000,000		1,000,000
Balance at Jun. 30, 2019	$ 123,424,216		$ 123,424,216
Balance, Shares at Mar. 31, 2019			1,000,000
Balance at Mar. 31, 2019			$ 126,383,351
Purchases of Shares			$ 25,158,095
Purchases of Shares, Shares			200,000
Redemption of Shares			$ (24,951,919)
Redemptions of Shares, Shares			(200,000)
Net Increase (Decrease) due to Share Transactions			$ 206,176
Net Increase (Decrease) due to Share Transactions, Shares			0
Net Comprehensive Income (Loss)	(16,438)	(16,438)
Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings	$ 16,438	$ 16,438	$ (16,438)
Adjustment of Redeemable Capital Shares to Redemption Value			$ (3,148,873)
Balance, Shares at Jun. 30, 2019	1,000,000		1,000,000
Balance at Jun. 30, 2019	$ 123,424,216		$ 123,424,216