ACQUISITIONS - Summary of purchase consideration and allocation of purchase consideration (Details) (USD $)	3 Months Ended		0 Months Ended			1 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Jan. 01, 2015	Dec. 31, 2014		Jan. 31, 2015
Purchase Price:
Cash paid	$ 35,887,000	$ 0
Buckingham Coal Company, LLC
Purchase Price:
Cash paid - Initial payment			34,000,000
Cash received - Working capital adjustment			(1,600,000)
Cash paid			32,400,000
Assets:
Cash and cash equivalents			2,800,000
Inventories - materials and supplies			2,000,000
Inventories - coal			0
Other current assets			100,000
Total current assets			4,900,000
Land and mineral rights			11,000,000
Plant and equipment			24,700,000
Total Assets			40,600,000
Liabilities:
Trade payables and other accrued liabilities			(4,400,000)
Asset retirement obligations			(1,000,000)
Total current liabilities			(5,400,000)
Asset retirement obligations, less current portion			(2,800,000)
Total Liabilities			(8,200,000)
Net fair value			32,400,000
Westmoreland Resources GP, LLC
Purchase Price:
Cash paid				30,000,000		3,500,000
Contingent consideration				3,500,000
Fair value of outstanding WMLP units				10,800,000	[1]
Total purchase consideration				44,300,000
Assets:
Trade receivables and other				22,500,000
Inventories - materials and supplies				7,400,000
Inventories - coal				6,600,000
Other current assets				1,300,000
Total current assets				37,800,000
Land and mineral rights				38,600,000
Plant and equipment				134,000,000
Advanced coal royalties				9,200,000
Restricted investments and bond collateral				10,600,000
Intangible assets				31,000,000
Other assets				200,000
Total Assets				261,400,000
Liabilities:
Trade payables and other accrued liabilities				(19,100,000)
Asset retirement obligations				(7,800,000)
Other current liabilities				(4,000,000)
Total current liabilities				(30,900,000)
Long-term debt, less current installments				(160,100,000)
Asset retirement obligations, less current portion				(23,900,000)
Warrants				(2,000,000)
Other liabilities				(200,000)
Total Liabilities				(217,100,000)
Net fair value				44,300,000
Non-controlling Interest				(10,800,000)
Invested Equity				$ 33,500,000
WMLP units outstanding, closing price (in USD per share)				$ 1.00

[1] Represents the market price of WMLP units outstanding using the December 31, 2014 closing price of $1.00.