Share-Based Compensation (Summary Of Stock Option Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified					12 Months Ended
	Dec. 31, 2011 years	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2011 1997 Plan	Dec. 31, 2010 1997 Plan	Dec. 31, 2009 1997 Plan	Dec. 31, 2011 2005 Plan	Dec. 31, 2010 2005 Plan	Dec. 31, 2009 2005 Plan
Options outstanding, January 1	509,422	384,507	253,836	159,668
Options granted								340,000	395,000	275,000
Options forfeited								(16,668)
Options exercised					(15,000)	(48,717)	(15,000)	(183,417)	(215,612)	(165,832)
Options outstanding, December 31,	509,422	384,507	253,836	159,668
Options exercisable December 31,	335,830
Weighted Average Exercise Price, January 1, Outstanding	$ 42.03	$ 33.24	$ 27.72	$ 29.03
Weighted Average Exercise Price, Grants in Period								$ 46.11	$ 36.18	$ 25.29
Weighted Average Exercise Price, Exercises in Period					$ 23.79	$ 31.56	$ 23.90	$ 32.69	$ 31.78	$ 25.18
Weighted Average Exercise Price, Forfeitures in Period								$ 41.52
Weighted Average Exercise Price, December 31, Outstanding	$ 42.03	$ 33.24	$ 27.72	$ 29.03
Weighted Average Exercise Price, Exercisable December 31,	$ 41.92
Contractual Life, Weighted Average, Outstanding	4.69
Contractual Life, Weighted Average, Exercisable	4.35
Intrinsic Value, Outstanding	$ 993
Intrinsic Value, Exercisable	$ 692