Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 03, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	HALLADOR ENERGY COMPANY
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		29,955,713
Amendment Flag	false
Entity Central Index Key	0000788965
Entity Filer Category	Accelerated Filer
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
Trading Symbol	HNRG