CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net income (loss)	$ (24,919)	$ (24,478)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and depletion	46,788	56,683
Accretion	5,359	5,532
Impairments	800	0
Loss (income) from unconsolidated affiliates, net of tax	(269)	(771)
Distributions of income from unconsolidated affiliates	1,000	4,500
Equity-based compensation expense	(1,648)	6,095
(Gain) loss on derivative financial instruments	(730)	3,102
Cash received (paid) on derivative financial instruments settlements	0	(1,968)
Non-cash interest expense related to early retirement of debt and refinancings	1,611	702
Payment of deferred financing costs	(3,640)	0
Net periodic postretirement benefit cost (credit)	(22,792)	(4,103)
Payments for logistics contracts	(7,500)	(20,438)
Logistics throughput contract amortization expense	12,099	27,419
Other	5,296	6,388
Changes in operating assets and liabilities:
Accounts receivable	(12,192)	(4,391)
Inventories, net	3,398	(1,212)
Due to or from related parties	(1,488)	(1,169)
Other assets	8,698	(5,545)
Accounts payable and accrued expenses	15,013	11,405
Asset retirement obligations	(816)	(719)
Net cash provided by (used in) operating activities	24,068	57,032
Investing activities
Purchases of property, plant and equipment	(7,165)	(11,327)
Investment in development projects	(1,894)	(2,110)
Other	69	33
Net cash provided by (used in) investing activities	(8,990)	(13,404)
Financing activities
Principal payments on federal coal leases	(574)	0
Repayment of senior notes	0	(62,094)
Payment of debt refinancing costs	0	(408)
Payments of deferred financing costs	(936)	0
Payment amortized to deferred gain	(6,298)	(6,294)
Proceeds from issuance of common stock	0	68,850
Cash paid for equity offering	0	(4,490)
Other	(1,952)	(1,958)
Net cash provided by (used in) financing activities	(9,760)	(6,394)
Net increase (decrease) in cash, cash equivalents, and restricted cash	5,318	37,234
Cash, cash equivalents, and restricted cash at beginning of period	108,673	84,433
Cash, cash equivalents, and restricted cash at end of period	$ 113,991	$ 121,667