Earnings Per Share (Schedule Of Computation Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Earnings, Income	$ 26,975	$ 24,363	$ 51,512	$ 44,937
Diluted earnings, Income	$ 26,975	$ 24,363	$ 51,512	$ 44,937
Earnings per Share	$ 1.60	$ 1.41	$ 3.05	$ 2.59
Earnings per Share, Diluted	$ 1.55	$ 1.36	$ 2.96	$ 2.48
Net Income, Earnings, Shares	16,880	17,236	16,872	17,374
Dilutive stock options, Shares	390	376	395	374
Nonvested stock awards, Shares	149	147	152	147
Conversion of Notes, Shares		121		202
Net Income, Diluted Earnings, Shares	17,419	17,880	17,419	18,097