Investments (Gross Unrealized Losses And Fair Value Of Investments) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Investments [Line Items]
Securities available-for-sale, Less Than Twelve Months, Estimated Fair Value	$ 292,528	$ 187,052
Securities available-for-sale, Less Than Twelve Months, Unrealized Loss	7,479	2,054
Securities available-for-sale, Twelve Months or Greater, Estimated Fair Value	153,002	162,016
Securities available-for-sale, Twelve Months or Greater, Unrealized Loss	8,703	5,871
Securities available-for-sale, Total, Estimated Fair Value	445,530	349,068
Securities available-for-sale, Total, Unrealized Loss	16,182	7,925
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	39,433	7,182
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	219	25
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	39,433	7,182
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss	219	25
Obligations Of States And Political Subdivisions
Schedule of Investments [Line Items]
Securities available-for-sale, Less Than Twelve Months, Estimated Fair Value	24,204	4,913
Securities available-for-sale, Less Than Twelve Months, Unrealized Loss	211	28
Securities available-for-sale, Twelve Months or Greater, Estimated Fair Value	18,955	19,440
Securities available-for-sale, Twelve Months or Greater, Unrealized Loss	799	379
Securities available-for-sale, Total, Estimated Fair Value	43,159	24,353
Securities available-for-sale, Total, Unrealized Loss	1,010	407
U.S. Government Agencies Mortgage-backed Securities
Schedule of Investments [Line Items]
Securities available-for-sale, Less Than Twelve Months, Estimated Fair Value	266,824	172,807
Securities available-for-sale, Less Than Twelve Months, Unrealized Loss	7,208	1,887
Securities available-for-sale, Twelve Months or Greater, Estimated Fair Value	134,047	140,226
Securities available-for-sale, Twelve Months or Greater, Unrealized Loss	7,904	5,418
Securities available-for-sale, Total, Estimated Fair Value	400,871	313,033
Securities available-for-sale, Total, Unrealized Loss	15,112	7,305
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	39,433	7,182
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	219	25
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	39,433	7,182
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss	219	25
Corporate Securities
Schedule of Investments [Line Items]
Securities available-for-sale, Less Than Twelve Months, Estimated Fair Value	0	3,357
Securities available-for-sale, Less Than Twelve Months, Unrealized Loss	0	49
Securities available-for-sale, Twelve Months or Greater, Estimated Fair Value	0	2,350
Securities available-for-sale, Twelve Months or Greater, Unrealized Loss	0	74
Securities available-for-sale, Total, Estimated Fair Value	0	5,707
Securities available-for-sale, Total, Unrealized Loss	0	123
Money Market Funds
Schedule of Investments [Line Items]
Securities available-for-sale, Less Than Twelve Months, Estimated Fair Value	1,500	1,500
Securities available-for-sale, Less Than Twelve Months, Unrealized Loss	60	36
Securities available-for-sale, Twelve Months or Greater, Estimated Fair Value	0	0
Securities available-for-sale, Twelve Months or Greater, Unrealized Loss	0	0
Securities available-for-sale, Total, Estimated Fair Value	1,500	1,500
Securities available-for-sale, Total, Unrealized Loss	$ 60	36
Trust Preferred Securities
Schedule of Investments [Line Items]
Securities available-for-sale, Less Than Twelve Months, Estimated Fair Value		4,475
Securities available-for-sale, Less Than Twelve Months, Unrealized Loss		54
Securities available-for-sale, Twelve Months or Greater, Estimated Fair Value		0
Securities available-for-sale, Twelve Months or Greater, Unrealized Loss		0
Securities available-for-sale, Total, Estimated Fair Value		4,475
Securities available-for-sale, Total, Unrealized Loss		$ 54