Basis of Presentation (Tables)

3 Months Ended

Mar. 31, 2012

Basis of Presentation [Abstract]

Summary of the effects of the correction of errors on the Condensed Consolidated Balance Sheet

	As of March 31, 2011
in thousands	As Reported		Correction			As Restated
Balance Sheet
Assets
Current deferred income taxes		$57,083		$910			$57,993
Prepaid expenses		24,300		735			25,035
Total current assets		765,250		1,645			766,895
Total assets		$8,298,791		$1,645			$8,300,436
Liabilities
Other current liabilities		$192,986		$16,676			$209,662
Total current liabilities		618,282		16,676			634,958
Noncurrent deferred income taxes		812,878		(5,849	)		807,029
Total liabilities		$4,393,174		$10,827			$4,404,001
Equity
Retained earnings		$1,425,668		($9,182	)		$1,416,486
Total equity		3,905,617		(9,182	)		3,896,435
Total liabilities and equity		$8,298,791		$1,645			$8,300,436