Summary Of Significant Accounting Policies And General (Details) T in Millions	1 Months Ended				3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 31, 2015 T	Sep. 30, 2014 USD ($)	Dec. 31, 2012 USD ($)	May. 31, 2008 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Loss from operations					$ 7,994,000	$ 6,108,000	$ 18,702,000	$ 11,421,000
Equity in net income (loss) of unconsolidated affiliate					77,000	(1,905,000)	342,000	(4,708,000)
Rhino Eastern LLC [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment charges									$ 5,900,000
Payments to acquire interest in joint venture				$ 16,100,000
Ownership interest equity method investment				51.00%
Interest acquired	49.00%
Coal Reserves | T	34
Muskie Proppant [Member]
Summary Of Significant Accounting Policies [Line Items]
Payments to acquire interest in joint venture			$ 2,000,000					200,000
Loss from operations						37,000		$ (81,000)
Loans to joint venture										$ 200,000
Sturgeon Acquisitions [Member]
Summary Of Significant Accounting Policies [Line Items]
Payments to acquire interest in joint venture		$ 5,000,000				$ 5,000,000
Ownership interest		100.00%				100.00%		100.00%
Equity in net income (loss) of unconsolidated affiliate					100,000		300,000
Mammoth [Member]
Summary Of Significant Accounting Policies [Line Items]
Equity method investment					$ 1,900,000		$ 1,900,000