Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets
Cash and cash equivalents	$ 133,956	$ 280,286
Investments, at fair value	326,344	251,254
Inventories	126,963	130,307
Trade receivables	723	1,277
Deferred income taxes	16,642	21,055
Prepaid expenses	4,220	2,546
Other current assets	21,744	14,671
Total current assets	630,592	701,396
Mineral properties	112,480	159,252
Mine development, net	452,110	409,754
Property, plant and equipment, net	112,827	118,881
Deferred debt issuance costs	4,367	6,032
Other noncurrent assets	4,811	4,012
Total assets	1,317,187	1,399,327
Current liabilities
Accounts payable	25,850	26,806
Accrued compensation and benefits	29,911	29,973
Property, production and franchise taxes payable	13,890	15,828
Current portion of long-term debt and capital lease obligations	1,185	2,144
Other current liabilities	6,625	7,288
Total current liabilities	77,461	82,039
Long-term debt and capital lease obligations	254,684	294,023
Deferred income taxes	48,907	68,896
Accrued workers compensation	6,092	6,060
Asset retirement obligation	10,805	9,401
Other noncurrent liabilities	9,307	7,200
Total liabilities	407,256	467,619
Stockholders’ equity
Preferred stock, $0.01 par value, 1,000,000 shares authorized; none issued	0	0
Common stock, $0.01 par value, 200,000,000 shares authorized; issued and outstanding 120,995,912 and 120,381,746 at September 30, 2015 and December 31, 2014, respectively	1,210	1,204
Paid-in capital	1,097,374	1,091,146
Accumulated deficit	(195,491)	(179,139)
Accumulated other comprehensive income	166	17
Total stockholders’ equity	903,259	913,228
Noncontrolling interest	6,672	18,480
Total equity	909,931	931,708
Total liabilities and equity	$ 1,317,187	$ 1,399,327