Fair Value (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	$ 943,275,000	$ 370,474,000
Investments, Fair Value Disclosure	0	0
Mortgage loans held for sale	17,800,000	31,700,000
Mortgage IRLCs	1,100,000	1,500,000
Investment securities	1,115,284,000	1,059,341,000
Loans Held-for-sale, Fair Value Disclosure	17,766,000	31,666,000
Impaired Loan Fair Value	7,484,000	6,924,000
Other Assets, Fair Value Disclosure	7,079,812,000	7,072,339,000
Loans Receivable, Fair Value Disclosure	7,106,142,000	7,112,474,000
Time deposits	827,039,000	870,804,000
Other Liabilities, Fair Value Disclosure	2,776,000	1,379,000
Deposits, Fair Value Disclosure	829,815,000	872,183,000
Short Term Borrowings Fair Value	305,385,000	342,230,000
Long-term debt	29,413,000	31,376,000
Subordinated Debt Obligations, Fair Value Disclosure	186,951,000	179,147,000
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	727,000	885,000
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	943,275,000	370,474,000
Mortgage IRLCs	0	0
Other Liabilities, Fair Value Disclosure	2,776,000	1,379,000
Deposits, Fair Value Disclosure	2,776,000	1,379,000
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage IRLCs	1,080,000	1,545,000
Investment securities	1,115,284,000	1,059,341,000
Loans Held-for-sale, Fair Value Disclosure	17,766,000	31,666,000
Loans Receivable, Fair Value Disclosure	18,846,000	33,211,000
Time deposits	827,039,000	870,804,000
Deposits, Fair Value Disclosure	827,039,000	870,804,000
Short Term Borrowings Fair Value	305,385,000	342,230,000
Long-term debt	29,413,000	31,376,000
Subordinated Debt Obligations, Fair Value Disclosure	186,951,000	179,147,000
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	7,484,000	6,924,000
Other Assets, Fair Value Disclosure	7,079,812,000	7,072,339,000
Loans Receivable, Fair Value Disclosure	7,087,296,000	7,079,263,000
Fair Value, Recurring [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage loans held for sale	17,766,000	31,666,000
Mortgage IRLCs	1,080,000	1,545,000
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	17,766,000	31,666,000
Mortgage IRLCs	1,080,000	1,545,000
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	298,313,000	305,218,000
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	298,313,000	305,218,000
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	814,909,000	752,109,000
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	814,909,000	752,109,000
Loans Receivable [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Swap	2,278,000	3,934,000
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	2,278,000	3,934,000
Swap	2,278,000	3,934,000
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	2,278,000	3,934,000
Swap	2,278,000	3,934,000
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	2,278,000	3,934,000
Swap	2,278,000	3,934,000
Equity Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investment securities	2,012,000	2,511,000
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investment securities	1,522,000	2,026,000
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investment securities	490,000	485,000
Equity Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments, Fair Value Disclosure	2,012,000	2,511,000
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	1,522,000	2,026,000
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	490,000	485,000
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	727,000	885,000
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
Corporate Debt Securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments, Fair Value Disclosure	2,062,000	2,014,000
Corporate Debt Securities | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments, Fair Value Disclosure	2,062,000	2,014,000
Reported Value Measurement [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	943,275,000	370,474,000
Mortgage IRLCs	1,080,000	1,545,000
Investment securities	1,115,284,000	1,059,341,000
Loans Held-for-sale, Fair Value Disclosure	17,766,000	31,666,000
Impaired Loan Fair Value	7,484,000	6,924,000
Other Assets, Fair Value Disclosure	7,055,529,000	7,051,975,000
Loans Receivable, Fair Value Disclosure	7,081,859,000	7,092,110,000
Time deposits	822,195,000	864,573,000
Other Liabilities, Fair Value Disclosure	2,776,000	1,379,000
Deposits, Fair Value Disclosure	824,971,000	865,952,000
Short Term Borrowings Fair Value	305,385,000	342,230,000
Long-term debt	30,000,000	32,500,000
Subordinated Debt Obligations, Fair Value Disclosure	187,881,000	187,774,000
Reported Value Measurement [Member] | Loans Receivable [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Mortgage IRLCs	2,278,000	3,934,000
Swap	2,278,000	3,934,000
Reported Value Measurement [Member] | Equity Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investment securities	2,012,000	2,511,000
Reported Value Measurement [Member] | Swap [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Swap	$ 226,000	$ 226,000