CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 30, 2014	Dec. 31, 2013
ASSETS
Cash and cash equivalents	$ 614,623,000	$ 260,818,000
Receivables, net	217,083,000	281,763,000
Inventories	226,074,000	312,647,000
Deferred income taxes	30,246,000	37,067,000
Prepaid expenses	43,320,000	39,022,000
Other current assets	12,999,000	18,031,000
Total current assets	1,144,345,000	949,348,000
Mineral interests, net	2,867,569,000	2,905,002,000
Property, plant and equipment, net	1,513,165,000	1,637,552,000
Other long-term assets	115,433,000	98,958,000
Total assets	5,640,512,000	5,590,860,000
LIABILITIES AND STOCKHOLDERS' EQUITY
Current debt	14,178,000	9,210,000
Accounts payable	51,894,000	92,712,000
Accrued expenses	179,673,000	133,870,000
Accumulated other postretirement benefits obligation	31,311,000	30,036,000
Other current liabilities	221,409,000	214,073,000
Total current liabilities	498,465,000	479,901,000
Long-term debt	3,176,219,000	2,769,622,000
Accumulated other postretirement benefits obligation	576,878,000	570,712,000
Deferred income taxes	751,565,000	822,867,000
Other long-term liabilities	182,467,000	195,064,000
Total liabilities	5,185,594,000	4,838,166,000
Stockholders' equity:
Common stock, $0.01 par value per share: Authorized—200,000,000 shares; issued—68,078,113 and 62,577,924 shares, respectively	681,000	626,000
Capital in excess of par value	1,654,467,000	1,613,256,000
Accumulated deficit	(1,041,401,000)	(698,930,000)
Accumulated deficit	(158,829,000)	(162,258,000)
Total stockholders' equity	454,918,000	752,694,000
Total liabilities and stockholders' equity	$ 5,640,512,000	$ 5,590,860,000