Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 30, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	SWIFT ENERGY CO
Entity Central Index Key	0000351817
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Document Period End Date	Sep. 30, 2015
Amendment Flag	false
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q3
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		44,550,975