SEGMENT INFORMATION (Details) $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2015 USD ($)		Jun. 30, 2014 USD ($)		Jun. 30, 2015 USD ($) segment		Jun. 30, 2014 USD ($)		Dec. 31, 2014 USD ($)
Segment information
Number of reportable segments | segment						4
Number of reportable segments corresponding to major coal producing regions in the eastern U.S. | segment						2
Reportable segment results
Revenues	[1]	$ 604,619		$ 598,464		$ 1,164,919		$ 1,140,398
Segment Adjusted EBITDA Expense	[2]	374,890		352,572		709,456		674,510
Segment Adjusted EBITDA	[3],[4]	199,807		232,709		408,707		440,459
Total assets		2,334,039	[5]	2,140,979	[5]	2,334,039	[5]	2,140,979	[5]	$ 2,288,755
Capital expenditures	[6]	57,428		85,115		107,758		155,979
Additional information
Equity in income (loss) of affiliates, net		(22,142)		(7,373)		(31,828)		(13,614)
Investments in affiliate		221,768				$ 221,768				$ 224,611
Payments to affiliate for acquisition and development of coal reserves								1,401
White Oak
Segment information
Number of operating segments within the reportable segment | segment						2
Operating segments | Illinois Basin
Reportable segment results
Revenues	[1]	406,862		424,523		$ 780,216		821,025
Segment Adjusted EBITDA Expense	[2]	244,843		255,942		471,055		485,533
Segment Adjusted EBITDA	[3],[4]	157,248		165,859		299,967		329,508
Total assets	[5]	1,192,634		1,102,550		1,192,634		1,102,550
Capital expenditures	[6]	34,466		62,166		68,208		117,875
Operating segments | Appalachia
Reportable segment results
Revenues	[1]	167,165		164,096		323,413		301,280
Segment Adjusted EBITDA Expense	[2]	118,744		93,917		216,559		179,490
Segment Adjusted EBITDA	[3],[4]	45,547		67,089		101,380		115,959
Total assets	[5]	580,059		608,714		580,059		608,714
Capital expenditures	[6]	21,701		18,541		37,439		28,669
Operating segments | White Oak
Reportable segment results
Revenues	[1]	18,718		4,170		37,086		7,868
Segment Adjusted EBITDA Expense	[2]	3,726		1,625		7,378		3,016
Segment Adjusted EBITDA	[3],[4]	(6,989)		(4,915)		(1,670)		(8,912)
Total assets	[5]	397,395		365,380		397,395		365,380
Capital expenditures	[6]	(37)		220		(22)		2,179
Additional information
Equity in income (loss) of affiliates, net		(22,000)		(7,500)		(31,400)		(13,800)
Investments in affiliate		190,500		174,900		190,500		174,900
Payments to affiliate for acquisition and development of coal reserves		0		0		0		1,400
Operating segments | Other and Corporate
Reportable segment results
Revenues	[1]	51,590		8,090		106,598		15,728
Segment Adjusted EBITDA Expense	[2]	44,137		3,503		90,620		11,974
Segment Adjusted EBITDA	[3],[4]	7,158		4,676		15,269		3,904
Total assets	[5]	320,353		65,884		320,353		65,884
Capital expenditures	[6]	1,298		4,188		2,133		7,256
Additional information
Equity in income (loss) of affiliates, net		(200)		100		(500)		100
Investments in affiliate		31,300		1,600		31,300		1,600
Elimination
Reportable segment results
Revenues	[1],[7]	(39,716)		(2,415)		(82,394)		(5,503)
Segment Adjusted EBITDA Expense	[2],[7]	(36,560)		(2,415)		(76,156)		(5,503)
Segment Adjusted EBITDA	[3],[4],[7]	(3,157)				(6,239)
Total assets	[5],[7]	$ (156,402)		$ (1,549)		$ (156,402)		$ (1,549)

[1] Revenues included in the Other and Corporate column are primarily attributable to the Matrix Group revenues, Mt. Vernon transloading revenues, Wildcat Insurance revenues and brokerage coal 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 three and six months ended June 30, 2015 of $(22.0) and $(31.4) million, respectively, included in the White Oak segment and $(0.2) million and $(0.5) million, respectively, included in the Other and Corporate segment.Includes equity in income (loss) of affiliates for the three and six months ended June 30, 2014 of $(7.5) million and $(13.8) million, respectively, included in the White Oak segment and $0.1 million, for each period, included in the Other and Corporate segment.

[4] Segment Adjusted EBITDA is defined as net income (prior to the allocation of noncontrolling interest) before net interest expense, income taxes, 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 $190.5 million and $31.3 million, respectively, at June 30, 2015 and $174.9 million and $1.6 million, respectively, at June 30, 2014.

[6] Capital expenditures shown above include funding to White Oak of $1.4 million for the six months ended June 30, 2014 and no funding for the three months ended June 30, 2015 and 2014 or for the six months ended June 30, 2015 for the acquisition and development of coal reserves (Note 8), which is described as “Payments to affiliate for acquisition and development of coal reserves” in our condensed consolidated statements of cash flow. Capital expenditures shown above exclude the Patriot acquisition on February 3, 2015 and MAC acquisition on January 1, 2015 (Note 4).

[7] The elimination column represents the elimination of intercompany transactions and is primarily comprised of sales from the Matrix Group to the ARLP Partnership’s mining operations, coal sales and purchases between operations within different segments, sales of receivables to AROP Funding and insurance premiums paid to Wildcat Insurance.