Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Accumulated other comprehensive income	$ 129,763	$ 118,056	$ 136,344	$ 110,538
Other Comprehensive Income Before Reclassifications	(11,823)	11,419
Reclassified from Accumulated Oher Comprehensive Income	1,209	708
Other Comprehensive Income (Loss), before Tax	(10,614)	12,127
Other Comprehensive Income (Loss), Tax	4,033	(4,609)
Other Comprehensive Income (Loss), Net of Tax	(6,581)	7,518
Unrealized Gain Loss on Securities OTTI [Member]
Accumulated other comprehensive income	4,382	(961)	3,245	(4,321)
Other Comprehensive Income Before Reclassifications	1,392	5,100
Reclassified from Accumulated Oher Comprehensive Income	442	320
Other Comprehensive Income (Loss), before Tax	1,834	5,420
Other Comprehensive Income (Loss), Tax	(697)	(2,060)
Other Comprehensive Income (Loss), Net of Tax	1,137	3,360
Unrealized Gain Loss on Securities Other [Member]
Accumulated other comprehensive income	152,070	139,843	160,263	136,137
Other Comprehensive Income Before Reclassifications	(13,215)	6,319
Reclassified from Accumulated Oher Comprehensive Income	0	(342)
Other Comprehensive Income (Loss), before Tax	(13,215)	5,977
Other Comprehensive Income (Loss), Tax	5,022	(2,271)
Other Comprehensive Income (Loss), Net of Tax	(8,193)	3,706
Pension Loss [Member]
Accumulated other comprehensive income	(26,689)	(20,826)	(27,164)	(21,278)
Other Comprehensive Income Before Reclassifications	0	0
Reclassified from Accumulated Oher Comprehensive Income	767	730
Other Comprehensive Income (Loss), before Tax	767	730
Other Comprehensive Income (Loss), Tax	(292)	(278)
Other Comprehensive Income (Loss), Net of Tax	$ 475	$ 452