Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Mar. 06, 2020	Jun. 28, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	HALLADOR ENERGY COMPANY
Document Type	10-K
Current Fiscal Year End Date	--12-31
Entity Public Float			$ 113,764,353
Entity Common Stock, Shares Outstanding		30,419,967
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Amendment Flag	false
Entity Central Index Key	0000788965
Entity Filer Category	Accelerated Filer
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Small Business	true