Stock-Based And Long-Term Incentive Compensation (Summary Of Compensation Expense and Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Compensation expense	$ 2,628	$ 19,692	$ 30,987
Related income taxes	610	4,569	7,189
Total compensation expense, net of income taxes	2,018	15,123	23,798
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Compensation expense	94	2,743	4,247
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Compensation expense	4,144	15,716	19,828
Cash Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Compensation expense	(56)	298
Performance Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Compensation expense	$ (1,554)	$ 935	$ 6,912