Impairments (Tables)

12 Months Ended

Dec. 31, 2013

Goodwill and Intangible Assets Disclosure [Abstract]

Details of Impairment of Long-Lived Assets Held and Used by Asset

The following table summarizes impairment charges recorded during the periods presented:

	Year Ended December 31,
	2013		2012		2011
Oil and gas properties	$	132,224	$	103,417	$	104,688
Other - tubular inventory and well materials	—		1,067		—
	$	132,224	$	104,484	$	104,688

Fair Value Measurements, Nonrecurring

The following table summarizes the aggregate fair values of the assets described below, by asset category and the classification of inputs within the fair value measurement hierarchy, at the respective dates of impairment:

	Fair Value
	Measurement		Level 1		Level 2		Level 3
Year ended December 31, 2013:
Long-lived assets held for use	$	93,945	$	—	$	—	$	93,945
Year ended December 31, 2012:
Long-lived assets held for use	$	14,801	$	—	$	—	$	14,801
Long-lived assets sold during the year	96,099		—		—		96,099
Year ended December 31, 2011:
Long-lived assets held for use	$	26,625	—		—		26,625
Long-lived assets sold during the year	30,342		—		—		30,342