Other Comprehensive Income (Loss) (Components Of Accumulated Other Comprehensive Income (Loss), Net Of Tax, In The Consolidated Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Other Comprehensive Income (Loss) [Abstract]
Beginning balance of URA (D) on securities	$ 201,154	$ 603,928	$ 603,928
Current period change in URA(D) of investments - temporary	55,269		(401,335)
Current period change in URA (D) of investments - non-credit OTTI	76		(1,439)
Ending balance of URA (D) on securities	256,499		201,154
Beginning balance of foreign currency translation adjustments	(4,530)	(4,368)	(4,368)
Current period change in foreign currency translation adjustments	(2,637)		(162)
Ending balance of foreign currency translation adjustments	(7,167)		(4,530)
Beginning balance of benefit plan net gain (loss)	(38,896)	(62,511)	(62,511)
Current period change in benefit plan net gain (loss)	771	1,346	23,615
Ending balance of benefit plan net gain (loss)	(38,125)		(38,896)
Accumulated other comprehensive income (loss)	$ 211,207		$ 157,728