Equity-Based Compensation Plans (Summary Of Outstanding Performance Share Awards / Restricted Stock Units) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Performance shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested shares outstanding at January 1, Shares	155,814	160,214	154,594
Granted (in shares)	87,441	83,111	85,028
Vested (in shares)	(76,202)	(71,861)	(76,812)
Forfeited (in shares)	(6,820)	(15,650)	(2,596)
Unvested shares outstanding at December 31, Shares	160,233	155,814	160,214
Unvested shares outstanding at January 1, Weighted Avg. Grant Date Fair Value (in dollars per share)	$ 48.73	$ 44.50	$ 50.54
Granted, Weighted Av.g Exercise Price (in dollars per share)	$ 45.57	$ 62.78	$ 34.24
Vested, Weighted Avg. Grant Date Fair Value (in dollars per share)	$ 34.24	$ 55.84	$ 45.30
Forfeited, Weighted Avg. Grant Date Fair Value (in dollars per share)	$ 49.75	$ 47.32	$ 44.99
Unvested shares outstanding at December 31, Weighted Avg. Grant Date Fair Value (in dollars per share)	$ 53.86	$ 48.73	$ 44.50
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	$ 2,609	$ 4,013	$ 3,480
Aggregate Intrinsic Value	6,709	6,504	6,019
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested shares outstanding at January 1, Shares	37,461	40,219	36,359
Granted (in shares)	19,599	23,449	20,225
Vested (in shares)	(21,333)	(19,796)	(14,861)
Forfeited (in shares)	(3,272)	(6,411)	(1,504)
Unvested shares outstanding at December 31, Shares	32,455	37,461	40,219
Unvested shares outstanding at January 1, Weighted Avg. Grant Date Fair Value (in dollars per share)	$ 38.69	$ 34.82	$ 35.60
Granted, Weighted Av.g Exercise Price (in dollars per share)	$ 40.51	$ 44.41	$ 31.53
Vested, Weighted Avg. Grant Date Fair Value (in dollars per share)	$ 34.46	$ 38.19	$ 32.41
Forfeited, Weighted Avg. Grant Date Fair Value (in dollars per share)	$ 42.06	$ 36.91	$ 33.36
Unvested shares outstanding at December 31, Weighted Avg. Grant Date Fair Value (in dollars per share)	$ 42.24	$ 38.69	$ 34.82
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	735	756	482
Aggregate Intrinsic Value	$ 1,359	$ 2,511	$ 1,575