Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
ASSETS
Cash and cash equivalents	$ 468,532	$ 260,818
Trade receivables, net	91,057	149,116
Other receivables	127,037	132,647
Inventories	201,598	312,647
Deferred income taxes	16,819	37,067
Prepaid expenses	46,190	39,022
Other current assets	19,542	18,031
Total current assets	970,775	949,348
Mineral interests, net	2,836,801	2,905,002
Property, plant and equipment, net	1,466,297	1,637,552
Other long-term assets	112,256	98,958
Total assets	5,386,129	5,590,860
LIABILITIES AND STOCKHOLDERS' EQUITY
Current debt	12,327	9,210
Accounts payable	38,980	92,712
Accrued expenses	125,318	133,870
Pension and other postretirement benefits obligation	29,032	37,125
Other current liabilities	215,952	206,984
Total current liabilities	421,609	479,901
Long-term debt	3,123,643	2,769,622
Pension and other postretirement benefits obligation	641,231	572,768
Deferred income taxes	730,685	822,867
Other long-term liabilities	187,380	193,008
Total liabilities	5,104,548	4,838,166
Commitments and Contingencies (Note 16)
Stockholders' equity:
Preferred stock, $.01 par value per share: Authorized-20,000,000 shares; none issued	0	0
Common stock, $0.01 par value per share: Authorized-200,000,000 shares; issued-71,978,113 and 62,577,924 shares, respectively	720	626
Capital in excess of par value	1,668,407	1,613,256
Accumulated deficit	(1,169,498)	(698,930)
Accumulated other comprehensive loss	(218,048)	(162,258)
Total stockholders' equity	281,581	752,694
Total liabilities and stockholders' equity	$ 5,386,129	$ 5,590,860