Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 31, 2019
Document And Entity Information [Abstract]
Entity Registrant Name	ULTRA PETROLEUM CORP.
Entity Central Index Key	0001022646
Document Type	10-Q
Document Period End Date	Jun. 30, 2019
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-33614
Entity Address, Address Line One	116 Inverness Drive East
Entity Address, Address Line Two	Suite 400
Entity Address, City or Town	Englewood
Entity Address, State or Province	Colorado
Entity Address, Postal Zip Code	80112
City Area Code	(303)
Local Phone Number	708-9740
Entity Common Stock, Shares Outstanding		197,840,056
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2