Stock-Based Compensation (Schedule Of Stock Option Plans Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Shares
Options outstanding, beginning balance (in shares)	63,000
Options exercised (in shares)	0
Options forfeited and expired (in shares)	0
Options outstanding, ending balance (in shares)	63,000	63,000
Options exercisable at end of year (in shares)	63,000
Weighted average exercise price
Exercised (usd per share)	$ 0
Options outstanding, ending balance (usd per share)	62.86	$ 62.86
Options exercisable at end of year (usd per share)	$ 62.86
Stock Options Plans
Shares
Options outstanding, beginning balance (in shares)	63,000	63,000	91,000
Options exercised (in shares)	0	0	(28,000)
Options forfeited and expired (in shares)	0	0	0
Options outstanding, ending balance (in shares)	63,000	63,000	63,000
Options exercisable at end of year (in shares)	63,000	63,000	63,000
Minimum | Stock Options Plans
Weighted average exercise price
Exercised (usd per share)	$ 0.00	$ 0.00	$ 57.34
Options forfeited and expired during the year (usd per share)	0.00	0.00	0.00
Options outstanding, ending balance (usd per share)	57.34	57.34	57.34
Options exercisable at end of year (usd per share)	57.34	57.34	57.34
Maximum | Stock Options Plans
Weighted average exercise price
Exercised (usd per share)	0.00	0.00	66.14
Options forfeited and expired during the year (usd per share)	0.00	0.00	0.00
Options outstanding, ending balance (usd per share)	66.14	66.14	66.14
Options exercisable at end of year (usd per share)	$ 66.14	$ 66.14	$ 66.14