FAIR VALUE (Tables)

12 Months Ended

Dec. 31, 2015

Marketable securities

FAIR VALUE

Schedule of carrying amounts and fair values of assets and liabilities

The carrying amounts and fair values of our marketable securities are as follows (thousands):

	As of December 31, 2015				As of December 31, 2014
	Carrying		Estimated		Carrying		Estimated
	Amount		Fair Value		Amount		Fair Value
Marketable securities	$	1,022	$	1,151	$	1,095	$	1,349

Long-term debt

FAIR VALUE

Schedule of carrying amounts and fair values of assets and liabilities

The carrying amounts and fair values of our debt are as follows (thousands):

	2015				2014
	Carrying		Estimated		Carrying		Estimated
	Amount		Fair Value		Amount		Fair Value
Total debt	$	3,371,679	$	3,616,946	$	3,242,470	$	3,716,513