Income Taxes (Tables)

12 Months Ended

Dec. 31, 2011

Summary of Provision for Income Taxes from Continuing Operations

The following table summarizes our provision for income taxes from continuing operations for the periods presented: 

	Year Ended December 31,
	2011			2010			2009
Current income taxes (benefit)
Federal	$	1,279		$	(109,240	)	$	(2,158	)
State		(3,933	)		876			(514	)
		(2,654	)		(108,364	)		(2,672	)
Deferred income taxes (benefit)
Federal		(80,529	)		67,999			(68,488	)
State		(4,972	)		(2,486	)		(14,734	)
		(85,501	)		65,513			(83,222	)
	$	(88,155	)	$	(42,851	)	$	(85,894	)

Intra Period Allocation of Income Taxes

The following table summarizes the intra-period allocation of income taxes for the periods presented: 

	Year Ended December 31,
	2011			2010			2009
Continuing operations	$	(88,155	)	$	(42,851	)	$	(85,894	)
Discontinued operations		-			3,384			10,642
Gain on sale of discontinued operations		-			35,116			-
	$	(88,155	)	$	(4,351	)	$	(75,252	)

Income Taxes Reconciliation

The following table reconciles the difference between the income taxes computed by applying the statutory tax rate to income from continuing operations before income taxes and our reported income tax expense for the periods presented: 

	Year Ended December 31,
	2011					2010					2009
Computed at federal statutory rate	$	(77,374	)	(35.0	)%	$	(37,862	)	(35.0	)%	$	(75,863	)	(35.0	)%
State income taxes, net of federal income tax benefit		(4,825	)	(2,2	)%		(1,927	)	(1.8	)%		(8,020	)	(3.7	)%
Other, net		(5,956	)	(2.7	)%		(3,062	)	(2.8	)%		(2,011	)	(0.9	)%
	$	(88,155	)	(39.9	)%	$	(42,851	)	(39.6	)%	$	(85,894	)	(39.6	)%

Summary of Principal Components of Net Deferred Income Tax Liability

The following table summarizes the principal components of our net deferred income tax liability as of the dates presented:

	As of December 31,
	2011			2010
Deferred tax liabilities:
Property and equipment	$	429,568		$	352,431
Fair value of derivative instruments		3,006			2,215
Convertible notes		60			6,143
Total deferred tax liabilities		432,634			360,789
Deferred tax assets:
Pension and postretirement benefits		3,046			3,951
Share-based compensation		8,838			7,602
Net operating loss carryforwards		150,953			27,915
Other		10,642			5,230
		173,479			44,698
Less:  Valuation allowance		(19,492	)		(19,063	)
Total deferred tax assets		153,987			25,635
Net deferred tax liability	$	278,647		$	335,154