RESTRICTED INVESTMENTS AND BOND COLLATERAL (Tables)

3 Months Ended

Mar. 31, 2013

Disclosure Restricted Investments and Bond Collateral [Abstract]

Components of restricted investments and bond collateral

The Company’s restricted investments and bond collateral consist of the following:

	March 31, 2013		December 31, 2012
	(In thousands)
Coal Segment:
WML debt reserve account	$	13,063	$	13,062
Reclamation bond collateral:
Kemmerer Mine	24,702		24,702
Absaloka Mine	14,532		14,507
Rosebud Mine	12,495		12,495
Beulah Mine	1,270		1,270
Power Segment:
Letter of credit account	5,993		5,990
Corporate Segment:
Postretirement medical benefit bonds	8,972		8,593
Workers’ compensation bonds	6,609		6,590
Total restricted investments and bond collateral	$	87,636	$	87,209

Carrying value and estimated fair value of restricted investments and bond collateral

The Company’s carrying value and estimated fair value of its restricted investments and bond collateral at March 31, 2013 are as follows:

	Carrying Value		Fair Value
	(In thousands)
Cash and cash equivalents	$	75,202	$	75,202
Time deposits	8,430		8,430
Held-to-maturity securities	3,812		4,149
Available-for-sale securities	192		192
	$	87,636	$	87,973

Amortized cost, gross unrealized holding gains and losses and fair value of held-to-maturity securities

The amortized cost, gross unrealized holding gains and fair value of held-to-maturity securities at March 31, 2013 is as follows (in thousands):

Amortized cost	$	3,812
Gross unrealized holding gains	337
Fair value	$	4,149

Maturities of held-to-maturity securities

Maturities of held-to-maturity securities are as follows at March 31, 2013:

	Amortized Cost		Fair Value
	(In thousands)
Due within one year	$	486	$	490
Due in five years or less	1,924		2,029
Due after five years to ten years	854		1,020
Due in more than ten years	548		610
	$	3,812	$	4,149

Cost basis, gross unrealized holding gains and fair value of available-for-sale securities

The cost basis, gross unrealized holding gains and fair value of available-for-sale securities at March 31, 2013 is as follows (in thousands):

Cost basis	$	175
Gross unrealized holding gains	17
Fair value	$	192