Note 15 - Segment Information - Adjusted EBITDA (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Net (Loss) Income		$ 126,291	$ (4,450)	$ 4,172	$ 26,404	$ 121,841	$ 30,576
Add: Income Tax Expense		23,223		(8,893)		19,701	(3,708)
Add: Interest Expense, net		13,121		16,187		27,473	31,448
Less: Interest Income		1,439		811		2,768	1,669
Earnings (Loss) Before Interest & Taxes (EBIT)		161,196		10,655		166,247	56,647
Depreciation, Depletion and Amortization		57,880		52,199		113,834	112,096
Earnings (Loss) Before Interest, Taxes and DD&A (EBITDA)		219,076		62,854		280,081	168,743
Stock-Based Compensation		1,269		1,210		5,470	2,719
Loss on Debt Extinguishment		(1,565)		106		(3,687)	789
Unrealized Mark-to-Market Gain on Commodity Derivative Instruments		(5,571)		20,437		96,331	20,437
Total Pre-tax Adjustments		(2,737)		21,563		105,488	22,389
Adjusted EBITDA	[1]	216,339		84,417		385,569	191,132
Pension Settlement				22			22
Add: Income Tax Expense		23,223		(8,893)		19,701	(3,708)
Loss on Debt Extinguishment		1,565		(106)		3,687	(789)
Pennsylvania Mining Complex [Member]
Net (Loss) Income		159,404		6,166		161,501	48,616
Add: Income Tax Expense		0		0		0	0
Add: Interest Expense, net		68		478		257	1,120
Less: Interest Income		452		36		866	36
Earnings (Loss) Before Interest & Taxes (EBIT)		159,020		6,608		160,892	49,700
Depreciation, Depletion and Amortization		49,465		50,169		100,421	104,950
Earnings (Loss) Before Interest, Taxes and DD&A (EBITDA)		208,485		56,777		261,313	154,650
Stock-Based Compensation		1,066		1,053		4,595	2,364
Loss on Debt Extinguishment		(0)		(0)		(0)	(0)
Unrealized Mark-to-Market Gain on Commodity Derivative Instruments		(5,571)		20,437		96,331	20,437
Total Pre-tax Adjustments		(4,505)		21,490		100,926	22,801
Adjusted EBITDA		203,980		78,267		362,239	177,451
Pension Settlement				0			0
Add: Income Tax Expense		0		0		0	0
Loss on Debt Extinguishment		0		0		0	0
CONSOL Marine Terminal [Member]
Net (Loss) Income		12,354		8,181		23,967	17,330
Add: Income Tax Expense		0		0		0	0
Add: Interest Expense, net		1,530		1,536		3,061	3,073
Less: Interest Income		(0)		(0)		(0)	(0)
Earnings (Loss) Before Interest & Taxes (EBIT)		13,884		9,717		27,028	20,403
Depreciation, Depletion and Amortization		1,142		1,200		2,307	2,414
Earnings (Loss) Before Interest, Taxes and DD&A (EBITDA)		15,026		10,917		29,335	22,817
Stock-Based Compensation		51		48		219	109
Loss on Debt Extinguishment		(0)		(0)		(0)	(0)
Unrealized Mark-to-Market Gain on Commodity Derivative Instruments		0		0		0	0
Total Pre-tax Adjustments		51		48		219	109
Adjusted EBITDA		15,077		10,965		29,554	22,926
Pension Settlement				0			0
Add: Income Tax Expense		0		0		0	0
Loss on Debt Extinguishment		0		0		0	0
Other Segments [Member]
Net (Loss) Income		(45,467)		(10,175)		(63,627)	(35,370)
Add: Income Tax Expense		23,223		(8,893)		19,701	(3,708)
Add: Interest Expense, net		11,523		14,173		24,155	27,255
Less: Interest Income		987		775		1,902	1,633
Earnings (Loss) Before Interest & Taxes (EBIT)		(11,708)		(5,670)		(21,673)	(13,456)
Depreciation, Depletion and Amortization		7,273		830		11,106	4,732
Earnings (Loss) Before Interest, Taxes and DD&A (EBITDA)		(4,435)		(4,840)		(10,567)	(8,724)
Stock-Based Compensation		152		109		656	246
Loss on Debt Extinguishment		(1,565)		106		(3,687)	789
Unrealized Mark-to-Market Gain on Commodity Derivative Instruments		0		0		0	0
Total Pre-tax Adjustments		1,717		25		4,343	(521)
Adjusted EBITDA		(2,718)		(4,815)		(6,224)	(9,245)
Pension Settlement				22			22
Add: Income Tax Expense		23,223		(8,893)		19,701	(3,708)
Loss on Debt Extinguishment		$ 1,565		$ (106)		$ 3,687	$ (789)

[1] Refer to “Reconciliation of Segment Information to Consolidated Amounts” for the reconciliation of Adjusted EBITDA, a non-GAAP measure, to its most directly comparable GAAP measure.