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Carrying amount of Securities Sold

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Debt Securities AFS Principal Sold

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Investment Securities Information

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Investment securities.

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Visa Restricted Stock Owned at Fair Value

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Visa Restricted Stock Owned at Zero Cost

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Visa Restricted Stock Owned. Total

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with interest rate reset through auction process, sold at par value.

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Amount of unrealized and realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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No definition available.

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Amount of allowance for credit loss for debt security measured at amortized cost (held-to-maturity).

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Amount of investment in debt security measured at amortized cost (held-to-maturity), past due.

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Amount of investment in debt security, measured at amortized cost, transferred to investment in debt security, measured at fair value, with change in fair value recognized in other comprehensive income (available-for-sale) and net income (trading).

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of investment in equity security without readily determinable fair value.

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Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Federal Reserve Bank stock represents an equity interest in the Federal Reserve Bank. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Net gain (loss) resulting from the sales of securitized, pay-through debt securities collateralized by real estate mortgage loans (mortgages).

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Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

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Sum of the carrying amounts as of the date of the latest financial statement presented of securities which are owned but transferred to another party to serve as collateral to partially or fully secure a debt obligation, repurchase agreement or other current or potential obligation, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

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Investment Securities (Details Textual) - USD ($)		3 Months Ended		12 Months Ended
Investment Securities (Details Textual) - USD ($)	Feb. 01, 2018	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2020
Investment Securities Information [Line Items]
Debt Securities, Available-for-sale, Sold at Par Value						$ 108,000,000
Interest receivable				$ 90,263,000	$ 91,196,000
Investment Securities (Textuals) [Abstract]
Debt Securities AFS Principal Sold		$ 261,000,000	$ 281,000,000		157,000,000
Gain (Loss) on Sales of Mortgage Backed Securities (MBS)		$ 3,000,000	$ 6,000,000
Transfer of HTM securities to AFS securities (adoption of ASU 2019-04)				$ 0	692,414,000	0
Debt Securities, Available-for-sale, Gain (Loss)					3,000,000
Carrying amount of Securities Sold					$ 1,200,000,000
Visa Restricted Stock Owned. Total				77,996
Visa Restricted Stock Owned at Fair Value [Member]					77,000
Visa Restricted Stock Donated [Member]					42,039
Debt Securities, Available-for-sale, Sold at Par Value						$ 108,000,000
Pledged Financial Instruments, Not Separately Reported, Securities				$ 1,600,000,000	$ 2,600,000,000
Debt Securities, Held-to-maturity, Past Due				0
Held to maturity allowance for credit loss				(67,000)			$ 61,000
Federal Home Loan Bank Stock				82,000,000	149,000,000
Federal Reserve Bank Stock				87,000,000	78,000,000
Interest receivable				90,263,000	91,196,000
Equity Securities with Readily Determined Fair Value				2,000,000	2,000,000
Equity Securities without Readily Determinable Fair Value, Amount				13,000,000	13,000,000
Visa Restricted Stock Owned at Zero Cost			996
First Staunton Bancshares
Investment Securities Information [Line Items]
Carrying amount of Securities Sold				84,000,000
Investment Securities (Textuals) [Abstract]
Carrying amount of Securities Sold				84,000,000
Bank Mutual [Member]
Investment Securities Information [Line Items]
Debt Securities, Available-for-sale, Sold at Par Value	$ 453,000,000
Investment Securities (Textuals) [Abstract]
Debt Securities, Available-for-sale, Sold at Par Value	$ 453,000,000
Securities Sold [Member]
Investment Securities Information [Line Items]
Taxable Equivalent Yield						3.08%
Commercial mortgage-related securities \| GNMA
Investment Securities Information [Line Items]
Debt Securities, Available-for-sale, Sold at Par Value						$ 40,000,000
Investment Securities (Textuals) [Abstract]
Debt Securities, Available-for-sale, Sold at Par Value						$ 40,000,000
Held-to-maturity Securities
Investment Securities Information [Line Items]
Interest receivable				14,000,000	16,000,000
Investment Securities (Textuals) [Abstract]
Interest receivable				14,000,000	16,000,000
Available-for-sale Securities [Member]
Investment Securities Information [Line Items]
Interest receivable				8,000,000	10,000,000
Investment Securities (Textuals) [Abstract]
Interest receivable				8,000,000	10,000,000
Federal Home Loan Bank Certificates and Obligations (FHLB) [Member]
Investment Securities Information [Line Items]
Interest receivable				972,000	2,000,000
Investment Securities (Textuals) [Abstract]
Interest receivable				972,000	2,000,000
Reinvestment [Member]
Investment Securities Information [Line Items]
Taxable Equivalent Yield						3.51%
Federal Reserve Bank Stock [Member]
Investment Securities Information [Line Items]
Interest receivable				0	0
Investment Securities (Textuals) [Abstract]
Interest receivable				$ 0	$ 0