Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current Assets:
Cash and cash equivalents	$ 277,077	$ 263,066
Short-term investments	21,849	75,143
Accounts receivable, net	58,706	120,881
Inventories, net	65,004	66,712
Prepaid expenses and other current assets	9,921	9,267
Deferred income taxes, net	0	22,295
Income tax deposits	6,583	746
Total current assets	439,140	558,110
Property, plant and mine development, net	561,196	565,755
Debt issuance costs, net	5,874	7,211
Goodwill		68,647
Trade names	14,474	14,914
Customer relationships, net	6,453	6,984
Other assets	18,709	12,317
Total assets	1,108,619	1,226,727
Current Liabilities:
Accounts payable	49,631	85,781
Dividends payable	3,453	6,805
Accrued liabilities	11,708	17,911
Accrued interest	58	60
Current portion of long-term debt	3,330	3,329
Current portion of deferred revenue	15,738	26,771
Total current liabilities	83,918	140,657
Long-term debt	488,375	491,757
Liability for pension and other post-retirement benefits	55,893	59,932
Deferred revenue	59,676	64,722
Deferred revenue	19,513	49,749
Other long-term obligations	17,077	16,094
Total liabilities	724,452	822,911
Stockholders’ Equity:
Preferred stock	0	0
Common stock	539	539
Additional paid-in capital	194,670	191,086
Additional paid-in capital	220,974	232,551
Retained earnings	(15,845)	(542)
Treasury stock, at cost	(16,171)	(19,818)
Accumulated other comprehensive loss	384,167	403,816
Total stockholders’ equity	$ 1,108,619	$ 1,226,727