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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 249	$ 11,984	$ 34,079	$ 24,242
Less: amounts capitalized	(1,179)	(2,112)	(5,870)	(4,904)
Total stock-based compensation expense (benefit)	(930)	9,872	28,209	19,338
Income tax benefit (expense)	(326)	3,627	9,874	7,097
Stock Appreciation Rights (SARs) [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	(8,935)	6,752	10,637	10,691
Restricted Stock Awards And Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	8,592	5,232	22,517	13,551
Performance Shares [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 592	$ 0	$ 925	$ 0