Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating activties
Net loss	$ (206,702)	$ (113,195)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation, depletion and amortization	63,699	104,874
Amortization of acquired sales contracts, net	(833)	(3,390)
Amortization relating to financing activities	3,150	6,219
Prepaid royalties expensed	1,286	1,674
Employee stock-based compensation expense	1,003	1,760
Asset impairment and non-cash mine closure costs	77,550	0
Non-cash bankruptcy reorganization items	(13,892)	0
Expenses related to proposed debt restructuring	2,213	0
Gains on disposals and divestitures, net	1	(46)
Deferred income taxes	(429)	(3,433)
Changes in:
Receivables	7,815	18,252
Inventories	734	(49,860)
Accounts payable, accrued expenses and other current liabilities	39,441	7,186
Income taxes, net	(642)	40
Other	15,508	25,646
Cash used in operating activities	(10,098)	(4,273)
Investing activities
Capital expenditures	(5,926)	(22,880)
Additions to prepaid royalties	(71)	(213)
Proceeds from disposals and divestitures	0	46
Purchases of marketable securities	(55,132)	(101,793)
Proceeds from sale or maturity of marketable securities and other investments	56,134	99,914
Investments in and advances to affiliates	(2,156)	(1,843)
Deposits of restricted cash	(12,108)	(3,532)
Cash used in investing activities	(19,259)	(30,301)
Financing activities
Payments on term loan	0	(4,875)
Net payments on other debt	(5,410)	(4,810)
Expenses related to proposed debt restructuring	(2,213)	0
Debt financing costs	(18,403)	0
Cash used in financing activities	(26,026)	(9,685)
Decrease in cash and cash equivalents	(55,383)	(44,259)
Cash and cash equivalents, beginning of period	450,781	734,231
Cash and cash equivalents, end of period	$ 395,398	$ 689,972