Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Significant Accounting Policies [Abstract]

Schedule Of Earnings Per Share

The following table provides a reconciliation of components of basic and diluted net income (loss) per common share:
		December 31,
		2011		2010		2009
Net income (loss)	$	453,202	$	464,459	$	(451,053)
Weighted average common shares outstanding
during the period		152,754		152,346		151,367
Effect of dilutive instruments		1,582		1,907		-	(1)
Weighted average common shares outstanding during
the period including the effects of dilutive instruments		154,336		154,253		151,367
Net income (loss) per common share - basic	$	2.97	$	3.05	$	(2.98)
Net income (loss) per common share - fully diluted	$	2.94	$	3.01	$	(2.98)
Number of shares not included in dilutive earnings per share that would have been anti-dilutive because the exercise price was greater than the average market price of
the common shares		1,030		1,214		-	(1)