SEGMENT INFORMATION (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Reconciliation of consolidated Segment Adjusted EBITDA Expense to operating expenses (excluding depreciation, depletion and amortization)
Segment Adjusted EBITDA Expense	$ 1,338,783	[1]	$ 1,185,047	[1]	$ 1,026,162	[1]
Outside coal purchases	(38,607)		(54,280)		(17,078)
Other income	3,115		983		851
Operating expenses (excluding depreciation, depletion and amortization)	$ 1,303,291		$ 1,131,750		$ 1,009,935

[1] 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.