Summary Of Significant Accounting Policies (Schedule Of Stock-Based Compensation Expense) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 11,984	$ 6,134	$ 24,242	$ 13,405
Less: amounts capitalized	(2,112)	(1,043)	(4,904)	(2,783)
Total Stock-Based Compensation Expense	9,872	5,091	19,338	10,622
Income Tax Benefit	(3,627)	(1,937)	(7,097)	(4,042)
Stock Options And SARs [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	6,752	1,536	10,691	226
Restricted Stock Awards And Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 5,232	$ 4,598	$ 13,551	$ 13,179