Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Significant Accounting Policies [Abstract]

Property and Equipment

Property and Equipment (in thousands)	December 31, 2011			December 31, 2010
Property and Equipment
Proved oil and gas properties	$	4,343,867		$	3,835,173
Unproved oil and gas properties		84,146			78,429
Furniture, fixtures, and other equipment		38,832			37,505
Less – Accumulated depreciation, depletion, and amortization		(2,599,079	)		(2,378,262	)
Property and Equipment, Net	$	1,867,766		$	1,572,845

Accounts Payable and Accrued Liabilities

(in thousands)	December 31, 2011		December 31, 2010
Trade accounts payable (1)	$	42,080	$	22,459
New Zealand deferred revenue		—		10,000
Accrued operating expenses		15,833		11,044
Accrued payroll costs		14,345		14,298
Asset retirement obligation – current portion		9,279		8,708
Accrued taxes		7,604		7,198
Other payables		6,825		1,887
Total accounts payable and accrued liabilities	$	95,966	$	75,594

(1) Included in “trade accounts payable” are liabilities of approximately $18.7 million and $8.1 million at December 31, 2011 and December 31, 2010, respectively, for outstanding checks. This represents the amounts by which checks were issued, but not presented by vendors to the Company’s banks for collection, exceeded balances in the applicable disbursement bank accounts.

Accumulated other comprehensive income (loss) and related tax effects for 2011 (in thousands)

	Gross Value			Tax Effect			Net of Tax Value
Other comprehensive gain (loss) at December 31, 2010	($	218	)	$	80		($	138	)
Change in fair value of cash flow hedges		(520	)		190			(330	)
Effect of cash flow hedges settled during the period		738			(270	)		468
Other comprehensive gain (loss) at December 31, 2011	$	—		$	—		$	—

Roll-forward of our asset retirement obligation

Asset Retirement Obligation as of December 31, 2008	$	48,785
Accretion expense		2,906
Liabilities incurred for new wells and facilities construction		3,400
Reductions due to sold and abandoned wells		(1,380	)
Revisions in estimates		10,525
Asset Retirement Obligation as of December 31, 2009	$	64,236
Accretion expense		3,956
Liabilities incurred for new wells and facilities construction		1,287
Reductions due to sold and abandoned wells		(749	)
Revisions in estimates		10,149
Asset Retirement Obligation as of December 31, 2010	$	78,879
Accretion expense		4,570
Liabilities incurred for new wells and facilities construction		590
Reductions due to sold and abandoned wells		(28,194	)
Revisions in estimates		20,548
Asset Retirement Obligation as of December 31, 2011	$	76,393