Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Mar. 08, 2019	Jun. 29, 2018
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			$ 125,602,524
Entity Common Stock, Shares Outstanding		30,244,599
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Trading Symbol	HNRG
Amendment Flag	false
Entity Central Index Key	0000788965
Entity Filer Category	Accelerated Filer
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY