Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 27, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	SWIFT ENERGY CO
Entity Central Index Key	0000351817
Document Type	10-K
Current Fiscal Year End Date	--12-31
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		11,465,688
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float	$ 124,874,291