Equity-Based Compensation (Summary Of Outstanding Performance Share Awards / Restricted Stock Units) (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Performance shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested shares outstanding at January 1, Shares	160,233
Granted (in shares)	78,974	87,441
Unvested shares outstanding at June 30, Shares	239,207.000
Unvested shares outstanding at January 1, Weighted Avg. Grant Date Fair Value (in dollars per share)	$ 53.86
Granted, Weighted Av.g Exercise Price (in dollars per share)	36.71	$ 45.57
Unvested shares outstanding at June 30, Weighted Avg. Grant Date Fair Value (in dollars per share)	$ 48.20
Aggregate Intrinsic Value	$ 8,112
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested shares outstanding at January 1, Shares	32,455
Granted (in shares)	27,820
Vested (in shares)	(2,400)
Unvested shares outstanding at June 30, Shares	57,875.000
Unvested shares outstanding at January 1, Weighted Avg. Grant Date Fair Value (in dollars per share)	$ 42.24
Granted, Weighted Av.g Exercise Price (in dollars per share)	39.99
Vested, Weighted Avg. Grant Date Fair Value (in dollars per share)	45.79
Unvested shares outstanding at June 30, Weighted Avg. Grant Date Fair Value (in dollars per share)	$ 41.01
Aggregate Intrinsic Value	$ 2,044