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 | | | $ 34,476,002 |
Purchases of Shares, Shares | | | 450,000 |
Redemption of Shares | | | $ (38,304,383) |
Redemption of Shares, Shares | | | (500,000) |
Net Increase (Decrease) due to Share Transactions | | | $ (3,828,381) |
Net Increase (Decrease) due to Share Transactions, shares | | | (50,000) |
Distributions | $ (381,372) | $ (381,372) | |
Net Comprehensive Income (Loss) | 452,160 | 452,160 | |
Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings | (70,788) | (70,788) | $ 70,788 |
Adjustment of Redeemable Capital Shares to Redemption Value | | | $ (5,178,792) |
Balance, Shares at Sep. 30, 2018 | | | 2,100,000 |
Temporary Equity, Balance at Sep. 30, 2018 | | | $ 160,334,837 |
Balance, Shares at Jun. 30, 2018 | | | 2,200,000 |
Temporary Equity, Balance at Jun. 30, 2018 | | | $ 165,042,657 |
Purchases of Shares | | | $ 3,601,678 |
Purchases of Shares, Shares | | | 50,000 |
Redemption of Shares | | | $ (11,290,577) |
Redemption of Shares, Shares | | | (150,000) |
Net Increase (Decrease) due to Share Transactions | | | $ (7,688,899) |
Net Increase (Decrease) due to Share Transactions, shares | | | (100,000) |
Distributions | (206,624) | (206,624) | |
Net Comprehensive Income (Loss) | 212,862 | 212,862 | |
Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings | $ (6,238) | (6,238) | $ 6,238 |
Adjustment of Redeemable Capital Shares to Redemption Value | | | $ 2,974,841 |
Balance, Shares at Sep. 30, 2018 | | | 2,100,000 |
Temporary Equity, Balance at Sep. 30, 2018 | | | $ 160,334,837 |
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 | | | $ 51,850,144 |
Purchases of Shares, Shares | | | 700,000 |
Redemption of Shares | | | $ (103,973,357) |
Redemption of Shares, Shares | | | (1,400,000) |
Net Increase (Decrease) due to Share Transactions | | | $ (52,123,213) |
Net Increase (Decrease) due to Share Transactions, shares | | | (700,000) |
Distributions | (753,725) | (753,725) | |
Net Comprehensive Income (Loss) | 753,436 | 753,436 | |
Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings | $ 289 | 289 | $ (289) |
Adjustment of Redeemable Capital Shares to Redemption Value | | | $ 5,079,863 |
Balance, Shares at Sep. 30, 2019 | 1,550,000 | | 1,550,000 |
Temporary Equity, Balance at Sep. 30, 2019 | $ 115,539,713 | | $ 115,539,713 |
Balance, Shares at Jun. 30, 2019 | | | 1,750,000 |
Temporary Equity, Balance at Jun. 30, 2019 | | | $ 132,186,489 |
Purchases of Shares | | | $ 14,888,978 |
Purchases of Shares, Shares | | | 200,000 |
Redemption of Shares | | | $ (29,836,573) |
Redemption of Shares, Shares | | | (400,000) |
Net Increase (Decrease) due to Share Transactions | | | $ (14,947,595) |
Net Increase (Decrease) due to Share Transactions, shares | | | (200,000) |
Distributions | (250,082) | (250,082) | |
Net Comprehensive Income (Loss) | 229,098 | 229,098 | |
Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings | $ 20,984 | $ 20,984 | $ (20,984) |
Adjustment of Redeemable Capital Shares to Redemption Value | | | $ (1,678,197) |
Balance, Shares at Sep. 30, 2019 | 1,550,000 | | 1,550,000 |
Temporary Equity, Balance at Sep. 30, 2019 | $ 115,539,713 | | $ 115,539,713 |