FAIR VALUE MEASUREMENTS (Tables)

12 Months Ended

Dec. 31, 2015

Fair Value Disclosures [Abstract]

Estimated fair values of Company's debt

The estimated fair value of the Company’s debt with fixed and variable interest rates are as follows:

	Fixed Interest Rate				Variable Interest Rate
	Carrying Value		Fair Value		Carrying Value		Fair Value
	(In thousands)				(In thousands)
December 31, 2015	$	345,984	$	213,500	$	619,341	$	388,380
December 31, 2014	$	345,533	$	348,283	$	516,300	$	519,750

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis

The table below sets forth, by level, the Company’s financial assets and liabilities that are accounted for at fair value on a recurring basis:

	Balance at December 31, 2015
				Quoted Prices in Active Markets for Identical Assets or Liabilities			Significant Other Observable Inputs
	Fair Value			Level 1			Level 2
	(In thousands)
Assets:
Available-for-sale investments included in Restricted investments and bond collateral	$	35,813		$	35,813		$	—
Available-for-sale investments included in Reclamation deposits	31,545			31,545			—
	$	67,358		$	67,358		$	—
Liabilities:
Contracts to purchase power included in Other current liabilities and Other liabilities	$	(37,335	)	$	—		$	(37,335	)
Warrants issued by WMLP included in Other liabilities	(646		)	(646		)
	$	(37,981	)	$	(646	)	$	(37,335	)

	Balance at December 31, 2014
				Quoted Prices in Active Markets for Identical Assets or Liabilities			Significant Other Observable Inputs
	Fair Value			Level 1			Level 2
	(In thousands)
Assets:
Available-for-sale investments included in Restricted investments and bond collateral	$	34,057		$	34,057		$	—
Available-for-sale investments included in Reclamation deposits	33,388			33,388			—
	$	67,445		$	67,445		$	—
Liabilities:
Contracts to purchase power included in Other current liabilities and Other liabilities	$	(29,368	)	$	—		$	(29,368	)
Warrants issued by WMLP included in Other liabilities	(1,981		)	(1,981		)
	$	(31,349	)	$	(1,981	)	$	(29,368	)