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 | | | 2,150,000 |
Temporary Equity, Balance at Dec. 31, 2017 | | | $ 169,271,222 |
Purchases of Shares | | | $ 30,874,324 |
Purchases of Shares, Shares | | | 400,000 |
Redemption of Shares | | | $ (27,013,806) |
Redemption of Shares, Shares | | | (350,000) |
Net Increase (Decrease) due to Share Transactions | | | $ 3,860,518 |
Net Increase (Decrease) due to Share Transactions, shares | | | 50,000 |
Distributions | $ (174,748) | $ (174,748) | |
Net Comprehensive Income (Loss) | 239,298 | 239,298 | |
Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings | (64,550) | (64,550) | $ 64,550 |
Adjustment of Redeemable Capital Shares to Redemption Value | | | $ (8,153,633) |
Balance, Shares at Jun. 30, 2018 | | | 2,200,000 |
Temporary Equity, Balance at Jun. 30, 2018 | | | $ 165,042,657 |
Balance, Shares at Mar. 31, 2018 | | | 2,200,000 |
Temporary Equity, Balance at Mar. 31, 2018 | | | $ 168,363,908 |
Purchases of Shares | | | $ 15,276,053 |
Purchases of Shares, Shares | | | 200,000 |
Redemption of Shares | | | $ (15,315,074) |
Redemption of Shares, Shares | | | (200,000) |
Net Increase (Decrease) due to Share Transactions | | | $ (39,021) |
Distributions | (114,058) | (114,058) | |
Net Comprehensive Income (Loss) | 145,195 | 145,195 | |
Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings | $ (31,137) | (31,137) | 31,137 |
Adjustment of Redeemable Capital Shares to Redemption Value | | | $ (3,313,367) |
Balance, Shares at Jun. 30, 2018 | | | 2,200,000 |
Temporary Equity, Balance at Jun. 30, 2018 | | | $ 165,042,657 |
Balance, Shares at Dec. 31, 2018 | 2,250,000 | | 2,250,000 |
Temporary Equity, Balance at Dec. 31, 2018 | $ 162,583,352 | | $ 162,583,352 |
Purchases of Shares | | | $ 36,961,166 |
Purchases of Shares, Shares | | | 500,000 |
Redemption of Shares | | | $ (74,136,784) |
Redemption of Shares, Shares | | | (1,000,000) |
Net Increase (Decrease) due to Share Transactions | | | $ (37,175,618) |
Net Increase (Decrease) due to Share Transactions, shares | | | (500,000) |
Distributions | (503,643) | (503,643) | |
Net Comprehensive Income (Loss) | 524,338 | 524,338 | |
Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings | $ (20,695) | (20,695) | $ 20,695 |
Adjustment of Redeemable Capital Shares to Redemption Value | | | $ 6,758,060 |
Balance, Shares at Jun. 30, 2019 | 1,750,000 | | 1,750,000 |
Temporary Equity, Balance at Jun. 30, 2019 | $ 132,186,489 | | $ 132,186,489 |
Balance, Shares at Mar. 31, 2019 | | | 1,750,000 |
Temporary Equity, Balance at Mar. 31, 2019 | | | $ 129,300,360 |
Purchases of Shares | | | $ 18,459,923 |
Purchases of Shares, Shares | | | 250,000 |
Redemption of Shares | | | $ (18,387,663) |
Redemption of Shares, Shares | | | (250,000) |
Net Increase (Decrease) due to Share Transactions | | | $ 72,260 |
Distributions | (246,634) | (246,634) | |
Net Comprehensive Income (Loss) | 244,462 | 244,462 | |
Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings | $ 2,172 | $ 2,172 | (2,172) |
Adjustment of Redeemable Capital Shares to Redemption Value | | | $ 2,816,041 |
Balance, Shares at Jun. 30, 2019 | 1,750,000 | | 1,750,000 |
Temporary Equity, Balance at Jun. 30, 2019 | $ 132,186,489 | | $ 132,186,489 |