Note 12 - Fair Value Measurement

12 Months Ended

Dec. 31, 2015

Fair Value Disclosures [Abstract]

Fair Value Disclosures [Text Block]

Note 12: Fair Value Measurement

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 8 for information on the fair values of our defined benefit pension plan assets.

	Balance at December 31, 2015		Balance at December 31, 2014		Input Hierarchy Level
Assets:
Cash and cash equivalents:
Money market funds and other bank deposits	$	155,209	$	209,665	Level 1
Non-current investments:
Equity securities – mining industry		1,515		4,920	Level 1
Trade accounts receivable:
Receivables from provisional concentrate sales		13,490		17,696	Level 2
Derivative contracts:
Base metal forward contracts		—		11,347	Level 2
Restricted cash balances:
Certificates of deposit and other bank deposits		999		883	Level 1
Total assets	$	171,213	$	244,511
Liabilities
Derivative contracts:
Base metal forward contracts	$	283	$	—	Level 2

Cash and cash equivalents consist primarily of money market funds and are valued at cost, which approximates fair value.

Current and non-current restricted cash balances consist primarily of certificates of deposit and U.S. Treasury securities and are valued at cost, which approximates fair value.

Our current and non-current investments consist of marketable equity securities which are valued using quoted market prices for each security multiplied by the number of shares held by us.

Trade accounts receivable consist of amounts due to us for shipments of concentrates and doré sold to customers.  Revenues and the corresponding accounts receivable for sales of metals products are recorded when title and risk of loss transfer to the customer (generally at the time of shipment).  Sales of concentrates are recorded using estimated forward prices for the anticipated month of settlement applied to our estimate of payable metal quantities contained in each shipment.  Sales are recorded net of estimated treatment and refining charges, which are also impacted by changes in metals prices and quantities of contained metals.  We must estimate the prices at which sales of our concentrates will be settled due to the time elapsed between shipment and final settlement with the customer.  Receivables for previously recorded concentrate sales are adjusted to reflect estimated settlement metals prices at the end of each period until final settlement by the customer.  We obtain the forward metals prices used each period from a pricing service.  Changes in metals prices between shipment and final settlement will result in changes to revenues previously recorded upon shipment.  The embedded derivative contained in our concentrate sales is adjusted to fair market value through earnings each period prior to final settlement.

We use financially-settled forward contracts to manage the exposure to changes in prices of silver, gold, zinc and lead contained in our concentrate shipments that have not reached final settlement.  At times we also use financially-settled forward contracts to manage the exposure to changes in prices of zinc and lead contained in our forecasted future concentrate shipments (see Note 10 for more information).  These contracts do not qualify for hedge accounting, and are marked-to-market through earnings each period.  The fair value of each contract represents the present value of the difference between the forward metal price for the contract settlement period as of the measurement date and the contract settlement metal price.

Our Senior Notes, which were recorded at their carrying value of $499.7 million, net of unamortized initial purchaser discount at December 31, 2015, had a fair value of $365.6 million at December 31, 2015. Third-party quotes, which we consider to be Level 2 inputs, are utilized to estimate fair values of the Senior Notes. See Note 6 for more information.