8. Additional Balance Sheet Detail

The following table summarizes components of selected balance sheet accounts as of the dates presented:

	March 31,		December 31,
	2012		2011
Other current assets:
Tubular inventory and well materials	$	8,170	$	14,251
Prepaid expenses		1,057		699
	$	9,227	$	14,950
Other assets:
Debt issuance costs	$	16,311	$	16,993
Assets of supplemental employee retirement plan ("SERP")		3,339		3,088
Other		49		51
	$	19,699	$	20,132
Accounts payable and accrued liabilities:
Trade accounts payable	$	41,162	$	30,186
Drilling costs		20,881		30,948
Royalties		15,035		15,235
Production and franchise taxes		2,695		3,495
Compensation		2,668		5,186
Interest		19,423		5,964
Other		1,909		3,490
	$	103,773	$	94,504
Other liabilities:
Asset retirement obligations	$	6,392	$	6,283
Defined benefit pension obligations		1,728		1,763
Postretirement health care benefit obligations		3,018		3,022
Deferred compensation - SERP obligation and other		3,413		3,172
Other		1,522		1,647
	$	16,073	$	15,887