FAIR VALUE MEASUREMENTS (Tables)

6 Months Ended

Jun. 30, 2018

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

Assets and liabilities measured at fair value on a recurring basis are summarized as follows (in thousands):



	Level 1		Level 2		Level 3		Total
June 30, 2018
Asset retirement obligations⁽¹⁾	$	—	$	—	$	1,771	$	1,771

December 31, 2017
Asset retirement obligations⁽¹⁾	—		—		1,936		1,936

⁽¹⁾

We calculate the fair value of asset retirement obligations by discounting the estimated amount using the current Treasury bill rate adjusted for our credit risk. At June 30, 2018, the balance is included in “Other long-term liabilities,” in the accompanying Condensed Consolidated Balance Sheets. At December 31, 2017, $0.2 million and $1.7 million were included in "Other current liabilities" and "Other long-term liabilities," respectively, in the accompanying Condensed Consolidated Balance Sheets.

Schedule of changes in asset retirement obligations

The following table provides a summary of changes in our Level 3 asset retirement obligations for the six months ended June 30, 2018 (in thousands):



Balance, January 1, 2018	$	1,936
Accretion	85
Payments	(250		)
Balance, June 30, 2018	$	1,771

Schedule of fair value of term loan and revolving credit facility

The fair values of our other Level 3 debt liabilities, estimated using a discounted cash flow analysis based on incremental borrowing rates for similar types of borrowing arrangements, are as follows (in thousands):



	June 30, 2018				December 31, 2017
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Term loan	$	431,321	$	435,096	$	298,500	$	301,485
Revolving credit facility	16,000		16,140		5,000		5,050