Note 10 - Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Abstract]

Fair value adjustments net

Fair value adjustments, net is comprised of the following:

	Year Ended December 31,
	2022			2021			2020
Gain (loss) on derivative contracts	$	844		$	(32,655	)	$	(22,074	)
Unrealized (loss) gain on investments in equity securities		(5,632	)		(4,295	)		10,268
Gain on disposition or exchange of investments		65			1,158			—
Total fair value adjustments, net	$	(4,723	)	$	(35,792	)	$	(11,806	)

Schedule of assets and liabilities at fair value on a recurring basis

The table below sets forth our assets and liabilities (in thousands) 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. See Note 5 for information on the fair values of our defined benefit pension plan assets.

	Balance at December 31, 2022		Balance at December 31, 2021		Input Hierarchy Level
Assets:
Cash and cash equivalents:
Money market funds and other bank deposits	$	104,743	$	210,010	Level 1
Current and non-current investments:
Equity securities – mining industry		24,018		14,470	Level 1
Trade accounts receivable:
Receivables from provisional concentrate sales		45,146		36,437	Level 2
Derivative contracts - other current assets and other non-current assets:
Metal forward and put option contracts		1,309		—	Level 2
Foreign exchange contracts		1,518		5,207	Level 2
Restricted cash balances:
Certificates of deposit and other deposits		1,164		1,053	Level 1
Total assets	$	177,898	$	267,177
Liabilities
Derivative contracts - current derivative liabilities and other non-current liabilities:
Metal forward and put option contracts	$	14,643	$	37,873	Level 2
Foreign exchange contracts		7,548		8	Level 2
Total liabilities	$	22,191	$	37,881