Investment Securities (Amortization Cost And Estimated Fair Value Of Investment Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Schedule Of Amortized Cost And Estimated Fair Values [Line Items]
Available-for-Sale Securities, Amortized Cost	$ 738,527	$ 687,631
Available-for-Sale Securities, Gross Unrealized Gains	22,298	13,620
Available-for-Sale Securities, Gross Unrealized Losses	(12,793)	(3,707)
Available-for-Sale Securities, Fair value	748,032	697,544
Corporate Bonds [Member]
Schedule Of Amortized Cost And Estimated Fair Values [Line Items]
Available-for-Sale Securities, Amortized Cost	119,000	119,000
Available-for-Sale Securities, Gross Unrealized Losses	(12,785)	(3,170)
Available-for-Sale Securities, Fair value	106,215	115,830
State And Municipals [Member]
Schedule Of Amortized Cost And Estimated Fair Values [Line Items]
Available-for-Sale Securities, Amortized Cost	358,607	372,113
Available-for-Sale Securities, Gross Unrealized Gains	14,950	10,269
Available-for-Sale Securities, Gross Unrealized Losses	(1)	(239)
Available-for-Sale Securities, Fair value	373,556	382,143
Pass-Through Mortgage Securities [Member]
Schedule Of Amortized Cost And Estimated Fair Values [Line Items]
Available-for-Sale Securities, Amortized Cost	114,139	60,307
Available-for-Sale Securities, Gross Unrealized Gains	2,860	1,104
Available-for-Sale Securities, Gross Unrealized Losses	(2)	(39)
Available-for-Sale Securities, Fair value	116,997	61,372
Collateralized Mortgage Obligations [Member]
Schedule Of Amortized Cost And Estimated Fair Values [Line Items]
Available-for-Sale Securities, Amortized Cost	146,781	136,211
Available-for-Sale Securities, Gross Unrealized Gains	4,488	2,247
Available-for-Sale Securities, Gross Unrealized Losses	(5)	(259)
Available-for-Sale Securities, Fair value	$ 151,264	$ 138,199