Impairments

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

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

In 2013, we recognized oil and gas impairments of $121.8 million in the Granite Wash in the Mid-Continent, $9.5 million in the Marcellus Shale in Pennsylvania and $0.9 million in the Selma Chalk in Mississippi, in each case due primarily to market declines in current and expected future commodity prices. In 2012, we recognized a $28.4 million impairment of our assets in West Virginia, Kentucky and Virginia triggered by the expected disposition of these properties, and a $75.0 million impairment of our Marcellus Shale assets due primarily to market declines in natural gas prices and the resultant reduction in proved natural gas reserves. In 2012, we also recognized an impairment of certain tubular inventory and well materials due primarily to declines in asset quality. In 2011, we recognized an impairment of our Arkoma Basin assets for $71.1 million, which was triggered by the expected disposition of these properties. Also during 2011, we recognized impairments of our horizontal coal bed methane properties in the Appalachian region for $26.6 million and certain dry-gas properties in Mississippi for $6.8 million, in each case due primarily to market declines in gas prices.