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, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Earnings	$ 66,456	$ 56,522	$ 130,625	$ 121,922
Diluted earnings	$ 66,456	$ 56,522	$ 130,625	$ 121,922
Earnings, Shares	14,932	15,829	14,959	15,919
Dilutive stock options, Shares	139	235	152	242
Nonvested stock awards, Shares	40	37	41	44
Diluted earnings, Shares	15,111	16,101	15,152	16,205
Earnings, Earnings per Share	$ 4.45	$ 3.57	$ 8.73	$ 7.66
Diluted earnings, Earnings per Share	$ 4.40	$ 3.51	$ 8.62	$ 7.52