Share-Based Compensation (Summary Of All RSU MSPs Granted To Employees And Non-Employee Directors) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
RSU outstanding at end of period, RSUs	206,685
RSU MSPs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
RSU outstanding at beginning of period, RSUs	78,732	69,293	62,896
Granted, RSUs	20,130	38,965	32,752
Settled, RSUs	(27,375)	(22,403)	(23,258)
Cancelled, RSUs	(3,563)	(7,123)	(3,097)
RSU outstanding at end of period, RSUs	67,924	78,732	69,293
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
RSU outstanding at beginning of period, Weighted Average Price	$ 37.46	$ 35.81	$ 25.67
Granted, Weighted Average Price	26.06	34.73	47.95
Settled, Weighted Average Price	29.94	27.87	25.94
Cancelled, Weighted Average Price	35.35	36.65	32.35
RSU outstanding at end of period, Weighted Average Price	$ 36.50	$ 37.46	$ 35.81