Revenue- Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Total revenue	$ 54,923	$ 54,688	$ 109,723	$ 106,232
Steam Coal Revenue [Member]
Total revenue	39,368	39,070	74,388	73,708
Met Coal Revenue [Member]
Total revenue	14,877	15,229	34,129	31,846
Other Revenue [Member]
Total revenue	678	389	1,206	678
Central Appalachia [Member]
Total revenue	28,133	25,674	59,108	48,989
Central Appalachia [Member] | Steam Coal Revenue [Member]
Total revenue	13,200	10,380	24,861	17,055
Central Appalachia [Member] | Met Coal Revenue [Member]
Total revenue	14,877	15,229	34,129	31,846
Central Appalachia [Member] | Other Revenue [Member]
Total revenue	56	65	118	88
Northern Appalachia [Member]
Total revenue	4,421	2,642	8,566	6,762
Northern Appalachia [Member] | Steam Coal Revenue [Member]
Total revenue	3,904	2,325	7,592	6,184
Northern Appalachia [Member] | Met Coal Revenue [Member]
Total revenue
Northern Appalachia [Member] | Other Revenue [Member]
Total revenue	517	317	974	578
Rhino Western [Member]
Total revenue	8,656	8,763	16,725	16,061
Rhino Western [Member] | Steam Coal Revenue [Member]
Total revenue	8,656	8,760	16,716	16,058
Rhino Western [Member] | Met Coal Revenue [Member]
Total revenue
Rhino Western [Member] | Other Revenue [Member]
Total revenue		3	9	3
Illinois Basin [Member]
Total revenue	13,608	17,604	25,219	34,412
Illinois Basin [Member] | Steam Coal Revenue [Member]
Total revenue	13,608	17,604	25,219	34,412
Illinois Basin [Member] | Met Coal Revenue [Member]
Total revenue
Illinois Basin [Member] | Other Revenue [Member]
Total revenue
Other [Member]
Total revenue	105	4	105	9
Other [Member] | Steam Coal Revenue [Member]
Total revenue
Other [Member] | Met Coal Revenue [Member]
Total revenue
Other [Member] | Other Revenue [Member]
Total revenue	$ 105	$ 4	$ 105	$ 9