Note 2 - Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Activity in Silver Bullion [Table Text Block]

Year Ended December 31, 2018	Ounces			Cost			Fair Value			Realized Gain (Loss)
Beginning balance		320,629,662		$	5,831,748,196		$	5,407,419,250		$	—
Silver bullion contributed		60,236,118			954,051,929			954,051,929			—
Silver bullion distributed		(62,004,144	)		(1,114,932,000	)		(982,882,736	)		(132,049,264	)
Silver bullion sold to pay expenses		(1,628,026	)		(29,309,969	)		(25,579,758	)		(3,730,211	)
Net realized loss		—			—			(135,779,475	)		—
Net change in unrealized appreciation/depreciation		—			—			(311,211,423	)		—
Ending balance		317,233,610		$	5,641,558,156		$	4,906,017,787		$	(135,779,475	)

Year Ended December 31, 2017	Ounces			Cost			Fair Value			Realized Gain (Loss)
Beginning balance		341,348,242		$	6,305,715,839		$	5,543,495,441		$	—
Silver bullion contributed		52,760,584			873,170,446			873,170,446			—
Silver bullion distributed		(71,810,555	)		(1,316,488,192	)		(1,226,578,286	)		(89,909,906	)
Silver bullion sold to pay expenses		(1,668,609	)		(30,649,897	)		(28,438,986	)		(2,210,911	)
Net realized loss		—			—			(92,120,817	)		—
Net change in unrealized appreciation/depreciation		—			—			337,891,452			—
Ending balance		320,629,662		$	5,831,748,196		$	5,407,419,250		$	(92,120,817	)

Year Ended December 31, 2016	Ounces			Cost			Fair Value			Realized Gain (Loss)
Beginning balance		317,934,907		$	5,979,251,955		$	4,393,860,514		$	—
Silver bullion contributed		97,670,323			1,702,628,324			1,702,628,324			—
Silver bullion distributed		(72,574,751	)		(1,344,950,576	)		(1,236,224,053	)		(108,726,523	)
Silver bullion sold to pay expenses		(1,682,237	)		(31,213,864	)		(28,700,680	)		(2,513,184	)
Net realized loss		—			—			(111,239,707	)		—
Net change in unrealized appreciation/depreciation		—			—			823,171,043			—
Ending balance		341,348,242		$	6,305,715,839		$	5,543,495,441		$	(111,239,707	)

Schedule of Capital Units [Table Text Block]

	December 31,
	2018						2017						2016
	Shares			Amount			Shares			Amount			Shares			Amount
Shares issued		64,000,000		$	954,051,929			55,800,000		$	873,170,446			102,750,000		$	1,702,628,324
Shares redeemed		(65,900,000	)		(982,882,736	)		(75,950,000	)		(1,226,578,286	)		(76,400,000	)		(1,236,224,053	)
Net increase (decrease)		(1,900,000	)	$	(28,830,807	)		(20,150,000	)	$	(353,407,840	)		26,350,000		$	466,404,271