Fair Value Measurement

The following tables summarize significant assets and liabilities measured at fair value in the consolidated balance sheets on a recurring basis for each of the fair value levels (in thousands):



	Fair Value Measurement at Reporting Date Using
December 31, 2017	Level 1		Level 2		Level 3		Total
Cash equivalents
Money market funds	$	37,284	$	—	$	—	$	37,284
Commercial paper	9,967		—		—		9,967
Total assets	$	47,251	$	—	$	—	$	47,251



	Fair Value Measurement at Reporting Date Using
December 31, 2016	Level 1		Level 2		Level 3		Total
Cash equivalents
Money market funds	$	10,057	$	—	$	—	$	10,057
Total assets	$	10,057	$	—	$	—	$	10,057

Derivatives

The commodity swaps that we entered in 2014 were settled in October 2015. Gains or losses, including net periodic settlement amounts, were recorded in other income, net in our consolidated statements of operations. During the year ended December 31, 2015, we recorded a net loss of $0.4 million.

Interest Rate Swaps

In December 2016, we terminated the fixed to variable interest rate swap we entered in March 2014 due to the possibility of increasing interest rates. The interest rate swap is reported at fair value using Level 2 inputs in the consolidated balance sheets. Gains or losses, including net periodic settlement amounts, are recorded in other income, net in our consolidated statements of operations. During the years ended December 31, 2016 and 2015, we recorded net gains of $0.3 million and $1.5 million, respectively.

In January 2016, we entered into an interest rate swap designated as a cash flow hedge with an effective date of April 2016 and an initial notional amount of $98.8 million which matures in October 2020. The interest rate swap is designed to convert the interest rate on the term loan described in Note 11 from a variable rate of interest of LIBOR plus an applicable margin to a fixed rate of 1.47% plus the same applicable margin. The interest rate swap is reported at fair value using Level 2 inputs in the consolidated balance sheets. Gains or losses on the effective portion are initially reported as a component of accumulated other comprehensive income (loss) and subsequently reclassified to interest expense in the consolidated statements of operations when the quarterly hedged interest payment is settled. As of December 31, 2017 and 2016, the fair value of the cash flow hedge was $1.4 million and $0.8 million, respectively, and was included in other current assets in the consolidated balance sheets. Associated gains or losses were recorded in the consolidated statements of operations and were immaterial during the years ended December 31, 2017 and 2016.

Other Assets and Liabilities

The carrying values and estimated fair values of our financial instruments that are not required to be recorded at fair value in the consolidated balance sheets are as follows (in thousands):



December 31,		2017				2016
	Fair Value Hierarchy	Carrying Value		Fair Value		Carrying Value		Fair Value
Assets:
Held-to-maturity marketable securities	Level 1	$	132,790	$	132,002	$	127,779	$	127,365
Liabilities (including current maturities):
Senior notes payable¹	Level 3	$	80,000	$	82,190	$	120,000	$	124,654
Credit Agreement term loan¹	Level 3	$	90,000	$	89,871	$	95,000	$	93,991
Credit Agreement - revolving credit facility, 2016 draw¹	Level 3	$	30,000	$	30,105	$	30,000	$	29,452
Credit Agreement - revolving credit facility, 2017 draw¹	Level 3	$	25,000	$	24,949	$	—	$	—

¹The fair values of the senior notes payable and Credit Agreement (defined in Note 11) loan are based on borrowing rates available to us for long-term loans with similar terms, average maturities, and credit risk.

We measure certain nonfinancial assets and liabilities at fair value on a nonrecurring basis, at least annually. As of December 31, 2017 and 2016, the nonfinancial assets and liabilities included our asset retirement and reclamation obligations, as well as assets and corresponding liabilities associated with performance guarantees.

The fair value of asset retirement obligations were measured using Level 3 inputs and performance guarantees were measured using Level 2 inputs. Asset retirement obligations were initially measured using internal discounted cash flow calculations based upon our estimates of future retirement costs - see Note 8 for details of the asset retirement balances and Note 1 for further discussion on fair value measurements. Performance guarantees were measured using estimated partner bond rates - see Note 10 for the liability balances and Note 1 for further discussion on performance guarantees.

During the years ended December 31, 2017, 2016 and 2015, nonfinancial assets and liabilities fair value adjustments were related to our asset retirement obligations and restructuring gains associated with our EIP, detailed as follows:


•	Asset retirement obligations adjustments were $0.5 million, $2.1 million and $0.2 million, respectively. See Note 8 for further information.

•

Restructuring gains associated with our EIP were $2.4 million, $1.9 million and $6.0 million (including amounts attributable to non-controlling interests of $3.3 million), during the years ended December 31, 2017, 2016 and 2015, respectively, primarily associated with the release of lease obligations, sale of a real estate asset related to our equity method investments and the sale of a previously impaired consolidated real estate asset.