CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME
Revenue	$ 301,673	$ 342,337	$ 863,374	$ 982,253
Costs and expenses
Cost of product sold (exclusive of depreciation, depletion, amortization, and accretion, shown separately)	248,500	288,345	735,258	830,405
Depreciation and depletion	7,896	25,815	51,742	81,944
Amortization of port access contract rights	928	0	2,783	0
Accretion	3,070	3,848	9,960	12,066
Derivative financial instruments	10,235	(515)	17,781	(16,052)
Selling, general and administrative expenses	12,940	12,163	36,701	37,086
Goodwill impairment	0	0	33,355	0
Other operating costs	646	1,099	1,163	1,671
Total costs and expenses	284,215	330,755	888,743	947,120
Gain on sale of Decker Mine interest	0	(74,262)	0	(74,262)
Operating income (loss)	17,458	85,844	(25,369)	109,395
Other income (expense)
Interest income	37	37	137	222
Interest expense	(10,985)	(12,701)	(36,274)	(64,508)
Tax agreement benefit	0	58,595	0	58,595
Other, net	253	(31)	158	(262)
Total other income (expense)	(10,695)	45,900	(35,979)	(5,953)
Income (loss) before income tax provision and earnings from unconsolidated affiliates	6,763	131,744	(61,348)	103,442
Income tax benefit (expense)	2,205	(40,688)	12,350	(30,709)
Income (loss) from unconsolidated affiliates, net of tax	(95)	13	294	562
Net income (loss)	8,873	91,069	(48,704)	73,295
Other comprehensive income (loss)
Postretirement medical plan amortization of prior service costs	313	247	939	741
Write-off of prior service costs related to Decker Mine pension	0	3,183	0	3,183
Income tax on postretirement medical plan	(116)	(1,235)	(347)	(1,413)
Other comprehensive income (loss)	197	2,195	592	2,511
Total comprehensive income (loss)	$ 9,070	$ 93,264	$ (48,112)	$ 75,806
Income (loss) per common share
Basic	$ 0.15	$ 1.5	$ (0.8)	$ 1.21
Diluted	$ 0.14	$ 1.49	$ (0.8)	$ 1.2
Weighted-average shares outstanding - basic	61,074	60,850	61,013	60,803
Weighted-average shares outstanding - diluted	61,351	61,133	61,013	61,197