SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 segment		Dec. 31, 2011		Dec. 31, 2010
Segment reporting information
Number of reportable segments	5
Number of reportable segments corresponding to major coal producing regions of eastern U.S.	3
Reportable segment results:
Total revenues	$ 2,033,930	[1]	$ 1,843,203	[1]	$ 1,609,743	[1]
Segment Adjusted EBITDA Expense	1,338,783	[2]	1,185,047	[2]	1,026,162	[2]
Segment Adjusted EBITDA	658,463	[3],[4]	622,813	[3],[4]	549,997	[4]
Total assets	1,958,840	[5]	1,734,477	[5]	1,504,072
Capital expenditures	459,232	[6]	372,720	[6]	289,874
Equity in income (loss) of affiliates	(14,650)		(3,404)
Investments in affiliate	88,513		40,118
Payments to affiliate for development of coal reserves	34,601		50,800
Illinois Basin
Reportable segment results:
Total revenues	1,499,976	[1]	1,313,148	[1]	1,202,442	[1]
Segment Adjusted EBITDA Expense	894,769	[2]	786,116	[2]	717,040	[2]
Segment Adjusted EBITDA	593,054	[3],[4]	505,113	[3],[4]	460,592	[4]
Total assets	1,042,719	[5]	787,923	[5]	745,626
Capital expenditures	219,029	[6]	153,118	[6]	149,149
Central Appalachia
Segment reporting information
Number of operating segments within the reportable segment	2
Reportable segment results:
Total revenues	157,311	[1]	206,323	[1]	165,175	[1]
Segment Adjusted EBITDA Expense	131,148	[2]	151,101	[2]	128,318	[2]
Segment Adjusted EBITDA	25,712	[3],[4]	53,729	[3],[4]	36,714	[4]
Total assets	87,068	[5]	96,099	[5]	81,818
Capital expenditures	33,817	[6]	28,477	[6]	10,012
Northern Appalachia
Reportable segment results:
Total revenues	335,099	[1]	274,233	[1]	219,211	[1]
Segment Adjusted EBITDA Expense	277,736	[2]	203,317	[2]	163,876	[2]
Segment Adjusted EBITDA	47,933	[3],[4]	62,395	[3],[4]	46,702	[4]
Total assets	537,042	[5]	452,407	[5]	313,515
Capital expenditures	109,039	[6]	137,040	[6]	128,961
White Oak
Segment reporting information
Number of operating segments within the reportable segment	2
Reportable segment results:
Segment Adjusted EBITDA Expense	(1,347)	[2]	155	[2]
Segment Adjusted EBITDA	(13,987)	[3],[4]	(4,407)	[3],[4]
Total assets	226,714	[5]	89,690	[5]
Capital expenditures	85,671	[5],[6]	51,198	[6]
Equity in income (loss) of affiliates	(15,300)		(4,300)
Investments in affiliate	86,800		38,500
Other and Corporate
Reportable segment results:
Total revenues	58,072	[1]	64,667	[1]	44,730	[1],[3]
Segment Adjusted EBITDA Expense	53,005	[2]	59,526	[2]	38,743	[2]
Segment Adjusted EBITDA	5,751	[3],[4]	5,983	[3],[4]	5,989	[4]
Total assets	66,396	[5]	309,213	[5]	367,199
Capital expenditures	11,676	[6]	2,887	[6]	1,752
Equity in income (loss) of affiliates	700		800
Investments in affiliate	1,700		1,600
Elimination
Reportable segment results:
Total revenues	(16,528)	[1]	(15,168)	[1]	(21,815)	[1]
Segment Adjusted EBITDA Expense	(16,528)	[2]	(15,168)	[2]	(21,815)	[2]
Total assets	$ (1,099)	[5]	$ (855)	[5]	$ (4,086)

[1] Revenues included in the Other and Corporate column are primarily attributable to Matrix Group revenues, Mt. Vernon transloading revenues and brokerage sales.

[2] Segment Adjusted EBITDA Expense includes operating expenses, outside coal purchases and other income. Transportation expenses are excluded as these expenses are passed through to the ARLP Partnership's customers and consequently it does not realize any gain or loss on transportation revenues. We review Segment Adjusted EBITDA Expense per ton for cost trends.

[3] Includes equity in income (loss) of affiliates for the year ended December 31, 2012 and 2011 of $(15.3) million and $(4.3) million, respectively included in the White Oak segment and $0.7 million and $0.8 million, respectively, included in the Other and Corporate segment

[4] Segment Adjusted EBITDA is defined as net income (prior to the allocation of noncontrolling interest) before income taxes, net interest expense, depreciation, depletion and amortization, and general and administrative expenses. Management therefore is able to focus solely on the evaluation of segment operating profitability as it relates to the ARLP Partnership's revenues and operating expenses, which are primarily controlled by our segments.

[5] Total assets for the White Oak and Other and Corporate Segments include investments in affiliate of $86.8 million and $1.7 million, respectively, at December 31, 2012 and $38.5 million and $1.6 million, respectively, at December 31, 2011.

[6] Capital expenditures shown above for the year ended December 31, 2012 and 2011 include $34.6 million and $50.8 million, respectively, for acquisition and development of coal reserves in our consolidated statements of cash flow. Capital expenditures shown above exclude the Green River acquisition on April 2, 2012 (Note 4).