Net Income (Loss) Per Share (Reconciliation Of Basic To Diluted Weighted Average Common Shares Outstanding) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Weighted Average Number of Shares Outstanding Reconciliation [Line Items]
Basic	122,480,000		115,869,000
Dilutive common stock options	150,000	[1]		[1]
Convertible senior notes dilution	3,460,000
Contingently issuable performance unit shares	157,000
Diluted	126,247,000		115,869,000
Stock Options [Member]
Weighted Average Number of Shares Outstanding Reconciliation [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	98,819
Investment Options, Exercise Price	113.77

[1] Options to purchase 98,819 shares of the Company's common stock at $113.77 were excluded from the diluted income per share calculations for the three months ended March 31, 2012 because they would have been anti-dilutive to the calculation.