Fair Value (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	$ 320,920,000	$ 159,956,000
Mortgage loans held for sale	23,900,000	12,300,000
Mortgage IRLCs	1,000,000.0	221,000
Investment securities	1,184,399,000	1,209,701,000
Loans Held-for-sale, Fair Value Disclosure	23,901,000	12,278,000
Impaired Loan Fair Value	2,154,000	2,090,000
Other Assets, Fair Value Disclosure	6,451,435,000	6,426,869,000
Loans Receivable, Fair Value Disclosure	6,478,525,000	6,441,458,000
Time deposits	1,069,209,000	1,145,537,000
Other Liabilities, Fair Value Disclosure	2,667,000	1,273,000
Deposits, Fair Value Disclosure	1,071,876,000	1,146,810,000
Short Term Borrowings Fair Value	193,373,000	230,657,000
Long-term debt	150,782,000	200,726,000
Subordinated Debt Obligations, Fair Value Disclosure	13,635,000	14,372,000
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	1,186,000	575,000
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	320,920,000	159,956,000
Mortgage IRLCs	0	0
Other Liabilities, Fair Value Disclosure	2,667,000	1,273,000
Deposits, Fair Value Disclosure	2,667,000	1,273,000
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage IRLCs	1,035,000	221,000
Investment securities	1,184,399,000	1,209,701,000
Loans Held-for-sale, Fair Value Disclosure	23,901,000	12,278,000
Loans Receivable, Fair Value Disclosure	24,936,000	12,499,000
Time deposits	1,069,209,000	1,145,537,000
Deposits, Fair Value Disclosure	1,069,209,000	1,145,537,000
Short Term Borrowings Fair Value	193,373,000	230,657,000
Long-term debt	150,782,000	200,726,000
Subordinated Debt Obligations, Fair Value Disclosure	13,635,000	14,372,000
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage IRLCs	0	0
Impaired Loan Fair Value	2,154,000	2,090,000
Other Assets, Fair Value Disclosure	6,451,435,000	6,426,869,000
Loans Receivable, Fair Value Disclosure	6,453,589,000	6,428,959,000
Fair Value, Recurring [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage loans held for sale	23,901,000	12,278,000
Mortgage IRLCs	1,035,000	221,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage loans held for sale	23,901,000	12,278,000
Mortgage IRLCs	1,035,000	221,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments, Fair Value Disclosure	320,766,000	320,491,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments, Fair Value Disclosure	320,766,000	320,491,000
U S Government Sponsored Entities Asset Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments, Fair Value Disclosure	863,633,000	889,210,000
U S Government Sponsored Entities Asset Backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments, Fair Value Disclosure	863,633,000	889,210,000
Loans Receivable [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Swap	4,617,000	1,870,000
Loans Receivable [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage IRLCs	0	0
Loans Receivable [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage IRLCs	4,617,000	1,870,000
Swap	4,617,000	1,870,000
Loans Receivable [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage IRLCs	0	0
Loans Receivable [Member] | Fair Value, Recurring [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage IRLCs	4,617,000	1,870,000
Swap	4,617,000	1,870,000
Loans Receivable [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage IRLCs	4,617,000	1,870,000
Swap	4,617,000	1,870,000
Equity Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investment securities	1,982,000	1,993,000
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investment securities	1,519,000	1,537,000
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investment securities	463,000	456,000
Equity Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments, Fair Value Disclosure	1,982,000	1,993,000
Equity Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments, Fair Value Disclosure	1,519,000	1,537,000
Equity Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments, Fair Value Disclosure	463,000	456,000
Swap [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Swap	226,000	226,000
Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	1,186,000	575,000
Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Swap	226,000	226,000
Swap [Member] | Fair Value, Recurring [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Swap	226,000	226,000
Swap [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Swap	226,000	226,000
Reported Value Measurement [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	320,920,000	159,956,000
Mortgage IRLCs	1,035,000	221,000
Investment securities	1,184,399,000	1,209,701,000
Loans Held-for-sale, Fair Value Disclosure	23,901,000	12,278,000
Impaired Loan Fair Value	2,154,000	2,090,000
Other Assets, Fair Value Disclosure	6,433,926,000	6,430,136,000
Loans Receivable, Fair Value Disclosure	6,461,016,000	6,444,725,000
Time deposits	1,060,835,000	1,139,131,000
Other Liabilities, Fair Value Disclosure	2,667,000	1,273,000
Deposits, Fair Value Disclosure	1,063,502,000	1,140,404,000
Short Term Borrowings Fair Value	193,373,000	230,657,000
Long-term debt	140,000,000	192,500,000
Subordinated Debt Obligations, Fair Value Disclosure	15,000,000	15,000,000
Reported Value Measurement [Member] | Loans Receivable [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage IRLCs	4,617,000	1,870,000
Swap	4,617,000	1,870,000
Reported Value Measurement [Member] | Equity Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investment securities	1,982,000	1,993,000
Reported Value Measurement [Member] | Swap [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Swap	$ 226,000	$ 226,000