XML 27 R30.htm IDEA: XBRL DOCUMENT

Property, Plant And Equipment (Narrative) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Property, Plant and Equipment [Line Items]
Impairment of oil and gas properties	$ 2,203	$ 1,536	$ 2,571	$ 2,917
Unproved Oil And Gas Properties [Member]
Property, Plant and Equipment [Line Items]
Impairment of oil and gas properties	$ 2,200	$ 1,500	$ 2,600	$ 2,900

The expense recorded to reduce the value of oil and gas assets consisting of proved properties and unproved properties as the estimate of future successful production from these properties is reduced.

+ References+ Details