Earnings Per Share (Schedule Of Computation Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share[Abstract]
Earnings	$ 219,923	$ 205,544	$ 98,177
Diluted earnings	$ 219,923	$ 205,544	$ 98,177
Earnings, Shares	15,969	16,059	16,057
Dilutive stock options, Shares	480	650	596
Nonvested stock awards, Shares	78	94	89
Diluted earnings, Shares	16,527	16,803	16,742
Earnings, Earnings per Share	$ 13.77	$ 12.80	$ 6.11
Diluted earnings, Earnings per Share	$ 13.31	$ 12.23	$ 5.86