Note 8 - Derivative Instruments (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

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

	March 31,		December 31,
Balance sheet line item:	2022		2021
Other current assets	$	3.9	$	2.7
Other non-current assets		3.9		2.5

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

March 31, 2022	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
2022 settlements		1,573		5		16,976		5,732	$	24.73	$	1,912	$	1.27	$	0.97
Contracts on forecasted sales
2022 settlements		—		—		37,644		46,517		N/A		N/A	$	1.31	$	0.98
2023 settlements		—		—		78,264		75,618		N/A		N/A	$	1.30	$	1.00
2024 settlements		—		—		64,650		23,149		N/A		N/A	$	1.32	$	1.01

December 31, 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
2022 settlements		1,814		6		13,371		4,575	$	23.02	$	1,812	$	1.39	$	0.96
Contracts on forecasted sales
2022 settlements		—		—		57,706		59,194		N/A		N/A	$	1.28	$	0.98
2023 settlements		—		—		76,280		71,650		N/A		N/A	$	1.29	$	1.00

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

	March 31, 2022								December 31, 2021
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)
Other current assets	$	0.3	$	(0.2	)	$	0.1		$	—	$	—		$	—
Current derivatives liability		0.5		(39.5	)		(39.0	)		0.7		(20.1	)		(19.4	)
Other non-current liabilities		0.1		(43.5	)		(43.4	)		0.4		(18.9	)		(18.5	)