SEGMENT INFORMATION - EBITDA Expense Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Reconciliation of consolidated Segment Adjusted EBITDA Expense to operating expenses (excluding depreciation, depletion and amortization)
Segment Adjusted EBITDA Expense	$ 1,139,637	$ 1,376,425	[1]	$ 1,381,808	[1]
Outside coal purchases	(1,514)	(327)		(14)
Other income	725	955		1,566
Operating expenses (excluding depreciation, depletion and amortization)	$ 1,138,848	$ 1,377,053		$ 1,383,360

[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.