Share-Based Compensation (Schedule Of Stock Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Options outstanding, January 1	871,671	516,674	211,675
Options outstanding, December 31	741,676	871,671	516,674
Options exercisable, December 31	476,663
Weighted Average Exercise Price, Options outstanding, January 1	$ 60.43	$ 59.20	$ 46.60
Weighted Average Exercise Price, Options outstanding, December 31	65.84	$ 60.43	$ 59.20
Weighted Average Exercise Price, Options exercisable, December 31	$ 64.12
Weighted Average Remaining Contractual Life (Years), Options outstanding, December 31	3 years 3 months 14 days
Weighted Average Remaining Contractual Life (Years), Options exercisable, December 31	2 years 11 months 25 days
Aggregate Intrinsic Value, Options outstanding, December 31	$ (3,683)
Aggregate Intrinsic Value, Options exercisable, December 31	$ (1,550)
2005 Plan [Member]
Options granted	20,000
Options exercised	(66,670)	(26,670)	(55,001)
Weighted Average Exercise Price, Options granted	$ 72.11
Weighted Average Exercise Price, Options exercised	$ 46.87	$ 47.52	$ 45.31
2012 Plan [Member]
Options granted	450,000	400,000	360,000
Options exercised	(421,657)	(3,333)
Options forfeited	(111,668)	(15,000)
Weighted Average Exercise Price, Options granted	$ 72.11	$ 61.31	$ 64.49
Weighted Average Exercise Price, Options exercised	63.03	61.31
Weighted Average Exercise Price, Options forfeited	$ 71.95	$ 64.49
Grant Date 2-22-2011 [Member]
Options outstanding, December 31	15,000
Weighted Average Exercise Price, Options outstanding, December 31	$ 45.58
Weighted Average Remaining Contractual Life (Years), Options outstanding, December 31	1 month 24 days
Grant Date 2-21-2012 [Member]
Options outstanding, December 31	48,334
Weighted Average Exercise Price, Options outstanding, December 31	$ 47.52
Weighted Average Remaining Contractual Life (Years), Options outstanding, December 31	1 year 1 month 24 days
Grant Date 2-25-2013 [Member]
Options outstanding, December 31	116,672
Weighted Average Exercise Price, Options outstanding, December 31	$ 64.49
Weighted Average Remaining Contractual Life (Years), Options outstanding, December 31	2 years 1 month 28 days
Grant Date 2-25-2014 [Member]
Options outstanding, December 31	201,670
Weighted Average Exercise Price, Options outstanding, December 31	$ 61.31
Weighted Average Remaining Contractual Life (Years), Options outstanding, December 31	3 years 1 month 28 days
Grant Date 2-20-2015 [Member]
Options outstanding, December 31	360,000
Weighted Average Exercise Price, Options outstanding, December 31	$ 72.11
Weighted Average Remaining Contractual Life (Years), Options outstanding, December 31	4 years 1 month 28 days