Fair Value Measurements (Financial Assets And Liabilities Measured At Fair Value) (Details) - USD ($) $ in Thousands	9 Months Ended			12 Months Ended
	Sep. 30, 2016		Sep. 30, 2015	Dec. 31, 2015
Deferred compensation plan investments (1)	$ 78,200	[1]		$ 53,600
Participant Withdrawals From Deferred Compensation Plan Investments	8,300			8,400
Diversification of share awards within deferred compensation plan	25,406		$ 3,558	3,600
Level 1 [Member]
Deferred compensation plan investments (1)	78,200	[1]		53,600
Level 2 [Member]
Deferred compensation plan investments (1)	0	[1]		0
Level 3 [Member]
Deferred compensation plan investments (1)	$ 0	[1]		$ 0

[1] Approximately $8.3 million and $8.4 million of participant cash was withdrawn from our deferred compensation plan investments during the nine months ended September 30, 2016 and the year ended December 31, 2015, respectively. Approximately $25.4 million and $3.6 million of shares in the compensation plan were diversified into the deferred compensation plan investments during the nine months ended September 30, 2016 and the year ended December 31, 2015, respectively.