Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Accumulated other comprehensive income		$ 102,929	$ 91,717	$ 32,470	$ 62,093
Other Comprehensive Income Before Reclassifications		112,937	49,636
Reclassified from Accumulated Oher Comprehensive Income		706	(1,854)
Other Comprehensive Income (Loss), before Tax		113,643	47,782
Other Comprehensive Income (Loss), Tax		(43,184)	(18,158)
Other comprehensive income (loss), net of tax		70,459	29,624
Unrealized Gain Loss on Securities OTTI [Member]
Accumulated other comprehensive income	[1]	2,918	3,663	3,316	3,791
Other Comprehensive Income Before Reclassifications	[1]	(765)	(223)
Reclassified from Accumulated Oher Comprehensive Income	[1]	123	17
Other Comprehensive Income (Loss), before Tax	[1]	(642)	(206)
Other Comprehensive Income (Loss), Tax	[1]	244	78
Other comprehensive income (loss), net of tax	[1]	(398)	(128)
Unrealized Gain Loss on Securities Other [Member]
Accumulated other comprehensive income	[1]	120,245	110,656	49,750	81,310
Other Comprehensive Income Before Reclassifications	[1]	113,702	49,859
Reclassified from Accumulated Oher Comprehensive Income	[1]	0	(2,526)
Other Comprehensive Income (Loss), before Tax	[1]	113,702	47,333
Other Comprehensive Income (Loss), Tax	[1]	(43,207)	(17,987)
Other comprehensive income (loss), net of tax	[1]	70,495	29,346
Pension Loss [Member]
Accumulated other comprehensive income	[2]	(20,234)	(22,602)	$ (20,596)	$ (23,008)
Other Comprehensive Income Before Reclassifications	[2]	0	0
Reclassified from Accumulated Oher Comprehensive Income	[2]	583	655
Other Comprehensive Income (Loss), before Tax	[2]	583	655
Other Comprehensive Income (Loss), Tax	[2]	(221)	(249)
Other comprehensive income (loss), net of tax	[2]	$ 362	$ 406

[1] The pre-tax amounts reclassified from accumulated other comprehensive income are included in "investment securities gains (losses), net" in the consolidated statements of income.

[2] The pre-tax amounts reclassified from accumulated other comprehensive income are included in the computation of net periodic pension cost as "amortization of prior service cost" and "amortization of unrecognized net loss" (see Note 6), for inclusion in the consolidated statements of income.