Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Accumulated other comprehensive income		$ 121,082	$ 65,636	$ 121,082	$ 65,636	$ 32,470	$ 62,093
Other Comprehensive Income Before Reclassifications				140,915	6,279
Reclassified from Accumulated Oher Comprehensive Income				2,007	(564)
Other Comprehensive Income (Loss), before Tax				142,922	5,715
Other Comprehensive Income (Loss), Tax				(54,310)	(2,172)
Other comprehensive income (loss), net of tax		(13,342)	16,847	88,612	3,543
Reclassification Where Impairment Was Not Previously Recognized				0	0
Unrealized Gain Loss on Securities OTTI [Member]
Accumulated other comprehensive income	[1]	2,964	3,528	2,964	3,528	3,316	3,791
Other Comprehensive Income Before Reclassifications	[1]			(837)	(976)
Reclassified from Accumulated Oher Comprehensive Income	[1]			270	483
Other Comprehensive Income (Loss), before Tax	[1]			(567)	(493)
Other Comprehensive Income (Loss), Tax	[1]			215	187
Other comprehensive income (loss), net of tax	[1]			(352)	(306)
Reclassification Where Impairment Was Not Previously Recognized	[1]			0	43
Unrealized Gain Loss on Securities Other [Member]
Accumulated other comprehensive income	[1]	137,637	84,021	137,637	84,021	49,750	81,310
Other Comprehensive Income Before Reclassifications	[1]			141,752	7,255
Reclassified from Accumulated Oher Comprehensive Income	[1]			0	(2,813)
Other Comprehensive Income (Loss), before Tax	[1]			141,752	4,442
Other Comprehensive Income (Loss), Tax	[1]			(53,865)	(1,688)
Other comprehensive income (loss), net of tax	[1]			87,887	2,754
Reclassification Where Impairment Was Not Previously Recognized	[1]			0	(43)
Pension Loss [Member]
Accumulated other comprehensive income	[2]	$ (19,519)	$ (21,913)	(19,519)	(21,913)	$ (20,596)	$ (23,008)
Other Comprehensive Income Before Reclassifications	[2]			0	0
Reclassified from Accumulated Oher Comprehensive Income	[2]			1,737	1,766
Other Comprehensive Income (Loss), before Tax	[2]			1,737	1,766
Other Comprehensive Income (Loss), Tax	[2]			(660)	(671)
Other comprehensive income (loss), net of tax	[2]			1,077	1,095
Reclassification Where Impairment Was Not Previously Recognized	[2]			$ 0	$ 0

[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.