Consolidated Condensed Statements of Comprehensive Income of Energen Corporation (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Net Income	$ 57,406	$ 94,268
Other Comprehensive Income (Loss):
Current period change in fair value of commodity derivative instruments, net of tax of ($7,498) and ($59,374)	(12,234)	(96,873)
Pension and postretirement plans:
Amortization of net obligation at transition, net of taxes of $25 and $24, respectively	47	44
Amortization of prior service cost, net of taxes of $30 and $26, respectively	55	48
Amortization of net loss, net of taxes of $412 and $318, respectively	766	590
Total pension and postretirement plans	868	682
Current period change in fair value of interest rate swap, net of tax ($265)	(492)	0
Comprehensive Income (Loss)	46,295	(5,606)
Commodity Contract [Member]
Other Comprehensive Income (Loss):
Reclassification adjustment for derivative instruments, net of tax	493	(3,683)
Interest Rate Swap [Member]
Other Comprehensive Income (Loss):
Reclassification adjustment for derivative instruments, net of tax	$ 254	$ 0