SECURITIES (Amortized Cost And Estimated Fair Values Of Available-For-Sale Securities) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 2,060,962	$ 2,218,468	$ 2,059,445
Gross Unrealized Gains	43,025	35,632	28,855
Gross Unrealized Losses	104	2,947	5,971
Estimated Fair Value	2,103,883	2,251,153	2,082,329
Gross gains recognized on available-for-sale securities	88	55
US Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,302,238	1,331,589	1,246,261
Gross Unrealized Gains	8,565	5,341	826
Gross Unrealized Losses		84	2,447
Estimated Fair Value	1,310,803	1,336,846	1,244,640
Government Agency Issued Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	177,195	214,390	138,759
Gross Unrealized Gains	3,066	3,518	1,957
Gross Unrealized Losses	83	717	176
Estimated Fair Value	180,178	217,191	140,540
Government Agency Issued Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	188,222	224,386	261,544
Gross Unrealized Gains	5,268	2,064	2,414
Gross Unrealized Losses	15	2,000	3,265
Estimated Fair Value	193,475	224,450	260,693
Obligations Of States And Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	374,134	434,980	394,769
Gross Unrealized Gains	25,263	23,488	22,813
Gross Unrealized Losses	6	146	83
Estimated Fair Value	399,391	458,322	417,499
Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	19,173	13,123	18,112
Gross Unrealized Gains	863	1,221	845
Estimated Fair Value	$ 20,036	$ 14,344	$ 18,957