Note 9 - Fair Value Measurement (Tables)

3 Months Ended

Mar. 31, 2023

Table Text Block [Abstract]

Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Table Text Block]

Fair value adjustments, net is comprised of the following:

	Three Months Ended March 31,
	2023		2022
Gain (loss) on derivative contracts	$	987	$	(201	)
Unrealized gain on equity securities investments		2,194		6,100
Gain on disposition or exchange of investments		—		66
Total fair value adjustments, net	$	3,181	$	5,965

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

The table below sets forth our assets and liabilities that were accounted for at fair value on a recurring basis and the fair value calculation input hierarchy level that we have determined applies to each asset and liability category (in thousands).

Description	Balance at March 31, 2023		Balance at December 31, 2022		Input Hierarchy Level
Assets:
Cash and cash equivalents:
Money market funds and other bank deposits	$	95,939	$	104,743	Level 1
Current and non-current investments
Equity securities - mining industry		26,434		24,018	Level 1
Trade accounts receivable:
Receivables from provisional concentrate sales		28,535		45,146	Level 2
Restricted cash balances:
Certificates of deposit and other deposits		1,347		1,164	Level 1
Derivative contracts - current and non-current derivatives assets:
Foreign exchange contracts		2,359		1,518	Level 2
Metal forward contracts		6,636		1,309	Level 2
Total assets	$	161,250	$	177,898
Liabilities:
Derivative contracts - current derivatives liabilities and other non-current liabilities:
Foreign exchange contracts	$	6,674	$	7,548	Level 2
Metal forward contracts		4,682		14,643	Level 2
Total liabilities	$	11,356	$	22,191