Condensed Consolidating Financial Information (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
ASSETS
Current assets	$ 328,151	$ 158,358
Property and equipment	1,867,766	1,572,845
Investment in subsidiaries (equity method)	0	0
Other assets	16,552	12,713
Total Assets	2,212,469	1,743,916
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	211,794	156,735
Long-term liabilities	1,004,166	707,164
Stockholders' equity	996,509	880,017
Total Liabilities and Stockholders Equity	2,212,469	1,743,916
Swift Energy Company (Parent and Issuer) [Member]
ASSETS
Current assets	0	0
Property and equipment	0	0
Investment in subsidiaries (equity method)	996,509	880,017
Other assets	0	0
Total Assets	996,509	880,017
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	0	0
Long-term liabilities	0	0
Stockholders' equity	996,509	880,017
Total Liabilities and Stockholders Equity	996,509	880,017
Swift Energy Operating, LLC (Guarantor) [Member]
ASSETS
Current assets	328,130	158,335
Property and equipment	1,867,766	1,572,845
Investment in subsidiaries (equity method)	0	0
Other assets	16,552	12,713
Total Assets	2,212,448	1,743,893
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	211,792	146,728
Long-term liabilities	1,089,595	788,385
Stockholders' equity	911,061	808,780
Total Liabilities and Stockholders Equity	2,212,448	1,743,893
Other Subsidiaries [Member]
ASSETS
Current assets	21	23
Property and equipment	0	0
Investment in subsidiaries (equity method)	911,061	808,780
Other assets	85,429	81,221
Total Assets	996,511	890,024
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	2	10,007
Long-term liabilities	0	0
Stockholders' equity	996,509	880,017
Total Liabilities and Stockholders Equity	996,511	890,024
Eliminations [Member]
ASSETS
Current assets	0	0
Property and equipment	0	0
Investment in subsidiaries (equity method)	(1,907,570)	(1,688,797)
Other assets	(85,429)	(81,221)
Total Assets	(1,992,999)	(1,770,018)
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	0	0
Long-term liabilities	(85,429)	(81,221)
Stockholders' equity	(1,907,570)	(1,688,797)
Total Liabilities and Stockholders Equity	$ (1,992,999)	$ (1,770,018)