Fair Value Measurement (Tables)
 12 Months Ended
Dec. 31, 2014
Fair Value Disclosures [Abstract]  
Fair value of financial instruments
Fair Value of Financial Instruments

The following table sets forth by level within the fair value hierarchy, our commodity derivative instruments and interest rate swap, included as part of Risk management assets and Risk management liabilities within the consolidated balance sheet, that were measured at fair value on a recurring basis as of December 31, 2014 and 2013 (in thousands):

 
Carrying
Amount
 
Estimated Fair Value of the Asset (Liability)
 
Level 1
 
Level 2
 
Level 3
 
Total
Commodity derivative instruments, net
 
 
 
 
 
 
 
 
 
December 31, 2014
$
286

 
$
—

 
$
286

 
$
—

 
$
286

December 31, 2013
(70
)
 
—

 
(70
)
 
—

 
(70
)
Interest rate swap
 
 
 
 
 
 
 
 
 
December 31, 2014
$
(215
)
 
$
—

 
$
(215
)
 
$
—

 
$
(215
)
December 31, 2013
(454
)
 
—

 
(454
)
 
—

 
(454
)

The unamortized portion of the premium paid to enter the weather derivative described in Note 7 "Derivatives," is included within Risk management assets on the consolidated balance sheet but is not included in the above table as it is recorded at amortized cost, not fair value.