Note 9 - Derivative Instruments (Tables)

9 Months Ended

Sep. 30, 2021

Notes Tables

Schedule of Foreign Exchange Contracts, Statement of Financial Position [Table Text Block]

	September 30,		December 31,
Balance sheet line item:	2021		2020
Current derivatives assets	$	2.5	$	3.5
Non-current derivatives assets		2.2		4.2
Current derivatives liability		—		—
Non-current derivative liability		0.2		—

Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]

September 30, 2021	Ounces/pounds under contract (in 000’s)								Average price per ounce/pound
	Silver		Gold		Zinc		Lead		Silver		Gold		Zinc		Lead
	(ounces)		(ounces)		(pounds)		(pounds)		(ounces)		(ounces)		(pounds)		(pounds)
Contracts on provisional sales
2021 settlements		1,190		4		20,867		9,866	$	23.15	$	1,776	$	1.35	$	1.01
Contracts on forecasted sales
2021 settlements		—		—		7,771		6,779		N/A		N/A	$	1.26	$	0.94
2022 settlements		—		—		60,043		63,769		N/A		N/A	$	1.28	$	0.98
2023 settlements		—		—		76,280		70,327		N/A		N/A	$	1.29	$	1.00
2024 settlements		—		—		43,762		—		N/A		N/A	$	1.31		N/A

December 31, 2020	Ounces/pounds under contract (in 000’s)								Average price per ounce/pound
	Silver		Gold		Zinc		Lead		Silver		Gold		Zinc		Lead
	(ounces)		(ounces)		(pounds)		(pounds)		(ounces)		(ounces)		(pounds)		(pounds)
Contracts on provisional sales
2021 settlements		1,282		4		23,314		4,905	$	25.00	$	1,858	$	1.19	$	0.90
Contracts on forecasted sales
2021 settlements		—		—		41,577		30,876		N/A		N/A	$	1.17	$	0.88
2022 settlements		—		—		18,519		—		N/A		N/A	$	1.28		N/A

Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position, Location [Table Text Block]

	September 30, 2021								December 31, 2020
Balance sheet line item:	Contracts in an asset position		Contracts in a liability position			Net asset (liability)			Contracts in an asset position		Contracts in a liability position			Net asset (liability)
Current derivatives assets	$	3.1	$	(0.4	)	$	2.7		$	0.2	$	(0.2	)	$	—
Non-current derivatives assets		7.1		(2.5	)		4.6			0.5		(0.1	)		0.4
Current derivatives liabilities		0.3		(4.4	)		(4.1	)		0.1		(11.8	)		(11.7	)
Non-current derivatives liabilities		1.2		(1.8	)		(0.6	)		—		—			—