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Fair Value Measurements (Carrying Amount, Estimated Fair Value, and Placement in Fair Value Hierarchy of Financial Instruments) (Details) - USD ($) $ in Thousands		Sep. 30, 2021	Dec. 31, 2020
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Securities available for sale		$ 1,097,950	$ 628,059
Securities held to maturity, fair value		224,164	282,035
Carrying Amount [Member] | Level 1 Inputs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash and cash equivalents		288,426	93,878
Accrued interest receivable		15,742	15,635
Non-maturity deposits		4,054,683	3,392,774
Short-term borrowings			5,300
Accrued interest payable		3,226	4,381
Carrying Amount [Member] | Level 2 Inputs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Securities available for sale		1,097,950	628,059
Securities held to maturity, fair value		218,135	271,973
Loans held for sale		5,916	4,305
Loans		3,553,901	3,513,284
Long-lived assets held for sale		4,341
FHLB and FRB stock		9,368	8,619
Time deposits		920,280	885,593
Long-term borrowings		73,834	73,623
Carrying Amount [Member] | Level 2 Inputs [Member] | Cash Flow Hedge of Interest Rate Risk [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative instruments, assets		1,112
Derivative instruments, liabilities			311
Carrying Amount [Member] | Level 2 Inputs [Member] | Interest Rate Products [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative instruments, assets		14,653	19,626
Derivative instruments, liabilities		14,658	19,837
Carrying Amount [Member] | Level 2 Inputs [Member] | Credit Contract [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative instruments, assets		0	23
Derivative instruments, liabilities		1	86
Carrying Amount [Member] | Level 2 Inputs [Member] | Mortgage Banking [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative instruments, assets		374	471
Derivative instruments, liabilities		5	1
Carrying Amount [Member] | Level 3 Inputs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loans	[1]	54,554	29,434
Estimated Fair Value [Member] | Level 1 Inputs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash and cash equivalents		288,426	93,878
Accrued interest receivable		15,742	15,635
Non-maturity deposits		4,054,683	3,392,774
Short-term borrowings			5,300
Accrued interest payable		3,226	4,381
Estimated Fair Value [Member] | Level 2 Inputs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Securities available for sale		1,097,950	628,059
Securities held to maturity, fair value		224,164	282,035
Loans held for sale		5,916	4,305
Loans		3,597,936	3,549,770
Long-lived assets held for sale		4,341
FHLB and FRB stock		9,368	8,619
Time deposits		920,221	887,113
Long-term borrowings		79,275	83,953
Estimated Fair Value [Member] | Level 2 Inputs [Member] | Cash Flow Hedge of Interest Rate Risk [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative instruments, assets		1,112
Derivative instruments, liabilities			311
Estimated Fair Value [Member] | Level 2 Inputs [Member] | Interest Rate Products [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative instruments, assets		14,653	19,626
Derivative instruments, liabilities		14,658	19,837
Estimated Fair Value [Member] | Level 2 Inputs [Member] | Credit Contract [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative instruments, assets		0	23
Derivative instruments, liabilities		1	86
Estimated Fair Value [Member] | Level 2 Inputs [Member] | Mortgage Banking [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative instruments, assets		374	471
Derivative instruments, liabilities		5	1
Estimated Fair Value [Member] | Level 3 Inputs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loans	[1]	$ 54,554	$ 29,434
[1] Comprised of collateral dependent loans.

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Fair value portion of liabilities incurred for goods and services received that are used in an entity's business and related party payables.

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Fair value portion of assets classified as held for sale.

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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).

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Amount of Federal Home Loan Bank (FHLB) and Federal Reserve Bank stock.

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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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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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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