Financial Instruments And Investments (Sale Of Securities And The Related Effects On Pre-Tax Income ) (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Investment [Line Items]
Proceeds from sales of available-for-sale securities	$ 31,435	$ 12,731	$ 67,841	$ 46,936	$ 82,561	$ 74,799
Gross realized gains included in pre-tax income	552	95	1,248	621	1,657	3,981
Gross realized losses included in pre-tax income	(289)	(288)	(583)	(960)	(512)	(1,327)
Gross unrealized losses included in pre-tax income	(1,547)	0	(1,746)	(263)	(1,746)	(408)
Net gains (losses) in pre-tax income	(1,284)	(193)	(1,081)	(602)	(601)	2,246
Net unrealized holding gains (losses) included in accumulated other comprehensive income	(7,503)	7,019	(4,914)	3,041	(1,290)	4,619
Net gains (losses) reclassified out of accumulated other comprehensive income	1,284	193	1,081	602	601	(2,246)
Net gains (losses) in other comprehensive income	$ (6,219)	$ 7,212	$ (3,833)	$ 3,643	$ (689)	$ 2,373