Statements of Changes in Net Assets (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net Assets, Beginning of Period	$ 775,343,105	$ 1,209,866,609
Operations:
Net investment income	1,028,255	4,491,037
Net realized gain (loss)	(224,167,336)	1,925,332
Net change in unrealized appreciation/depreciation	(144,962,309)	163,896,481
Net increase (decrease) in net assets resulting from operations	(368,101,390)	170,312,850
Capital Share Transactions:
Contributions for Shares issued	134,854,545	24,217,916
Distributions for Shares redeemed	(40,549,504)	(171,597,419)
Net increase (decrease) in net assets from capital share transactions	94,305,041	(147,379,503)
Increase (decrease) in net assets	(273,796,349)	22,933,347
Net Assets, End of Period	$ 501,546,756	$ 1,232,799,956
Shares issued and redeemed
Shares issued (in shares)	9,450,000	1,700,000
Shares redeemed (in shares)	(3,700,000)	(11,050,000)
Net increase (decrease) in Shares issued and outstanding (in shares)	5,750,000	(9,350,000)