Accounting Policies (Summary Of The Most Significant Impacts Of The New Accounting Guidance) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016
Increase in operating activities		$ 141,466	$ 137,873
Decrease in financing activities		62,087	75,697
Accounting Standards Update 2016-09 [Member]
Effective Income Tax Rate Reconciliation, Deduction, Amount	$ 7,100	$ 18,300
Weighted Average Number Diluted Shares Outstanding Adjustment	450,000	450,000
Accounting Standards Update 2016-09 [Member] | Tax Benefits Related To Share-based Payments At Settlement Classified As Operating Cash Flows Instead Of Financing Cash Flows [Member]
Increase in operating activities		$ 18,300
Decrease in financing activities		18,300
Accounting Standards Update 2016-09 [Member] | Cash Payments To Tax Authorities For Shares Withheld To Meet Tax Withholding Requirements On Restricted Stock Units Are Classified As Financing Cash Flow Instead Of Operating Cash Flow [Member]
Increase in operating activities		7,500	3,700
Decrease in financing activities		$ 7,500	$ 3,700