Investments (Aggregate Carrying And Approximate Market Values Of Available-For-Sale Securities) (Details) - USD ($)	Dec. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 1,570,449,000	$ 1,479,545,000
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	2,417,000	2,870,000
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	151,560,000	144,278,000
Debt Securities, Available-for-sale	1,421,306,000	1,338,137,000
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	199,131,000	228,456,000
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	139,000	371,000
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	15,519,000	16,089,000
Debt Securities, Available-for-sale	183,751,000	212,738,000
U.S. Government agencies
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	1,334,755,000	1,211,484,000
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	1,993,000	2,362,000
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	134,667,000	125,753,000
Debt Securities, Available-for-sale	1,202,081,000	1,088,093,000
Private label
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	5,096,000	6,997,000
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	0	0
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	163,000	293,000
Debt Securities, Available-for-sale	4,933,000	6,704,000
Trust preferred securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	4,605,000	4,599,000
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	141,000	0
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	0	321,000
Debt Securities, Available-for-sale	4,746,000	4,278,000
Corporate securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	26,862,000	28,009,000
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	144,000	137,000
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	1,211,000	1,822,000
Debt Securities, Available-for-sale	$ 25,795,000	$ 26,324,000