Summary Of Significant Accounting Policies (Schedule Of Stock-Based Compensation Expense) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 4,469	$ 2,501	$ 12,258	$ 7,272
Less: amounts capitalized	(1,486)	(985)	(2,792)	(1,740)
Total Stock-Based Compensation Expense	2,983	1,516	9,466	5,532
Income Tax Benefit	(1,107)	(562)	(3,470)	(2,052)
Stock Options And SARs [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	7	(2,975)	3,939	(1,309)
Restricted Stock Awards And Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 4,462	$ 5,476	$ 8,319	$ 8,581