CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
ASSETS
Cash and cash equivalents	$ 260,818	$ 116,601
Receivables, net	281,763	256,967
Inventories	312,647	306,018
Deferred income taxes	37,067	58,526
Prepaid expenses	39,022	53,776
Other current assets	18,031	23,928
Total current assets	949,348	815,816
Mineral interests, net	2,905,002	2,965,557
Property, plant and equipment, net	1,637,552	1,732,131
Deferred income taxes		160,422
Other long-term assets	98,958	94,494
Total assets	5,590,860	5,768,420
LIABILITIES AND STOCKHOLDERS' EQUITY
Current debt	9,210	18,793
Accounts payable	92,712	114,913
Accrued expenses	133,870	184,875
Accumulated other postretirement benefits obligation	30,036	29,200
Other current liabilities	214,073	206,473
Total current liabilities	479,901	554,254
Long-term debt	2,769,622	2,397,372
Accumulated other postretirement benefits obligation	570,712	633,264
Deferred income taxes	822,867	921,687
Other long-term liabilities	195,064	251,272
Total liabilities	4,838,166	4,757,849
Commitments and Contingencies (Note 18)
Stockholders' equity:
Common stock, $0.01 par value per share: Authorized-200,000,000 shares; issued-62,577,924 and 62,521,300 shares, respectively	626	625
Capital in excess of par value	1,613,256	1,628,244
Accumulated deficit	(698,930)	(347,448)
Accumulated other comprehensive loss	(162,258)	(270,850)
Total stockholders' equity	752,694	1,010,571
Total liabilities and stockholders' equity	$ 5,590,860	$ 5,768,420