Share-Based Compensation Plans (Schedule Of Restricted Stock, RSUs, Performance Restricted Stock and PSUs Activity) (Details)	12 Months Ended
	Dec. 31, 2023 $ / shares shares
RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Beginning balance, Number of shares | shares	112,100
Granted, Number of shares | shares	180,500
Vested, Number of shares | shares	(76,000)
Forfeited, Number of shares | shares	(11,200)
Ending balance, Number of shares | shares	205,400
Beginning balance, Weighted-average fair value at grant date | $ / shares	$ 86.66
Granted, Weighted-average fair value at grant date | $ / shares	73.61
Vested, Weighted-average fair value at grant date | $ / shares	(86.36)
Forfeited, Weighted-average fair value at grant date | $ / shares	(81.83)
Ending balance, Weighted-average fair value at grant date | $ / shares	$ 75.56
PSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Beginning balance, Number of shares | shares	306,400
Granted, Number of shares | shares	101,100
Performance adjustments, Number of shares | shares	(80,300)
Forfeited, Number of shares | shares	(18,700)
Ending balance, Number of shares | shares	308,500
Beginning balance, Weighted-average fair value at grant date | $ / shares	$ 99.38
Granted, Weighted-average fair value at grant date | $ / shares	98.06
Performance adjustments, Weighted-average fair value at grant date | $ / shares	(101.96)
Forfeited, Weighted-average fair value at grant date | $ / shares	(96.62)
Ending balance, Weighted-average fair value at grant date | $ / shares	$ 98.44
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Beginning balance, Number of shares | shares	50,700
Vested, Number of shares | shares	(50,600)
Forfeited, Number of shares | shares	(100)
Ending balance, Number of shares | shares
Beginning balance, Weighted-average fair value at grant date | $ / shares	$ 78.05
Vested, Weighted-average fair value at grant date | $ / shares	(78.05)
Forfeited, Weighted-average fair value at grant date | $ / shares	(77.22)
Ending balance, Weighted-average fair value at grant date | $ / shares	$ 0