Financial Instruments And Investments (Sale Of Securities And The Related Effects On Pre-Tax Income ) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Investment [Line Items]
Proceeds from sales of available-for-sale securities	$ 28,827	$ 10,907	$ 74,067	$ 89,870
Gross realized gains included in pre-tax income	3,014	39	3,961	1,128
Gross realized losses included in pre-tax income	(149)	(197)	(385)	(2,062)
Other than temporary impairment losses, recognized in earnings before tax	0	0	0	(479)
Net unrealized holding gains (losses) included in accumulated other comprehensive income	998	6,793	11,904	8,562
Net gains (losses) in pre-tax income	2,865	(158)	3,576	(1,413)
Net gains (losses) in other comprehensive income	$ (1,867)	$ 6,951	$ 8,328	$ 9,975