Investments (Gross Unrealized Losses And Fair Value Of Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Investments [Line Items]
Securities available-for-sale, Less Than Twelve Months, Estimated Fair Value	$ 187,052	$ 276,444
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2,054	8,087
Securities available-for-sale, Twelve Months or Greater, Estimated Fair Value	162,016	13,498
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	5,871	1,015
Securities available-for-sale, Total, Estimated Fair Value	349,068	289,942
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	7,925	9,102
Obligations of states and political subdivisions
Schedule of Investments [Line Items]
Securities available-for-sale, Less Than Twelve Months, Estimated Fair Value	4,913	35,108
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	28	1,474
Securities available-for-sale, Twelve Months or Greater, Estimated Fair Value	19,440	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	379	0
Securities available-for-sale, Total, Estimated Fair Value	24,353	35,108
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	407	1,474
U.S. Government agencies
Schedule of Investments [Line Items]
Securities available-for-sale, Less Than Twelve Months, Estimated Fair Value	172,807	225,530
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,887	6,099
Securities available-for-sale, Twelve Months or Greater, Estimated Fair Value	140,226	8,527
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	5,418	461
Securities available-for-sale, Total, Estimated Fair Value	313,033	234,057
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	7,305	6,560
Trust preferred securities
Schedule of Investments [Line Items]
Securities available-for-sale, Less Than Twelve Months, Estimated Fair Value	4,475	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	54	0
Securities available-for-sale, Twelve Months or Greater, Estimated Fair Value	0	4,971
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	554
Securities available-for-sale, Total, Estimated Fair Value	4,475	4,971
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	54	554
Corporate securities
Schedule of Investments [Line Items]
Securities available-for-sale, Less Than Twelve Months, Estimated Fair Value	3,357	14,306
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	49	478
Securities available-for-sale, Twelve Months or Greater, Estimated Fair Value	2,350	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	74	0
Securities available-for-sale, Total, Estimated Fair Value	5,707	14,306
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	123	478
Investment funds
Schedule of Investments [Line Items]
Securities available-for-sale, Less Than Twelve Months, Estimated Fair Value	1,500	1,500
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	36	36
Securities available-for-sale, Twelve Months or Greater, Estimated Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Securities available-for-sale, Total, Estimated Fair Value	1,500	1,500
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 36	$ 36