Compensation Plans (Range of Exercise Price Of Stock Appreciation Rights) (Details) - Stock Appreciation Rights (SARs) [Member] - United States Of America Dollars [Member] - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Outstanding Number	6,343	6,721	10,137
Weighted Average Remaining Contractual Life (years)	2 years 3 months 29 days
Outstanding, Weighted Average Exercise Price	$ 14.25	$ 14.55	$ 20.26
Exercisable Number	4,611	3,782
Exercisable, Weighted Average Exercise Price	$ 16.85	$ 18.02
0.00 to 9.99 [Member]
Exercise Price, Lower Range Limit	0.00
Exercise Price, Upper Range Limit	$ 9.99
Outstanding Number	1,311
Weighted Average Remaining Contractual Life (years)	5 years 2 months 1 day
Outstanding, Weighted Average Exercise Price	$ 4.06
Exercisable Number	301
Exercisable, Weighted Average Exercise Price	$ 4.06
10.00 to 19.99 [Member]
Exercise Price, Lower Range Limit	10.00
Exercise Price, Upper Range Limit	$ 19.99
Outstanding Number	4,707
Weighted Average Remaining Contractual Life (years)	1 year 7 months 2 days
Outstanding, Weighted Average Exercise Price	$ 16.52
Exercisable Number	3,985
Exercisable, Weighted Average Exercise Price	$ 17.36
20.00 to 29.99 [Member]
Exercise Price, Lower Range Limit	20.00
Exercise Price, Upper Range Limit	$ 29.99
Outstanding Number	325
Weighted Average Remaining Contractual Life (years)	1 year 6 months 29 days
Outstanding, Weighted Average Exercise Price	$ 22.46
Exercisable Number	325
Exercisable, Weighted Average Exercise Price	$ 22.46