Fair Value Measurements and Fair Value of Financial Instruments, Fair Value of Financial Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2021	Dec. 31, 2020
AFS securities [Abstract]
AFS securities	$ 1,576,030	$ 1,348,698
Equity securities	33,013	30,737
Fair Value Measurements [Abstract]
Collateral dependent impaired loans with specific reserve	12,500	15,200
Reserves on collateral dependent impaired loans	$ 1,300	3,200
Minimum [Member]
Fair Value Measurements [Abstract]
Liquidation expense ratio on impaired collateral	10.00%
Maximum [Member]
Fair Value Measurements [Abstract]
Liquidation expense ratio on impaired collateral	50.00%
Federal Agency [Member]
AFS securities [Abstract]
AFS securities	$ 242,966	243,597
State & Municipal [Member]
AFS securities [Abstract]
AFS securities	84,021	43,180
Corporate [Member]
AFS securities [Abstract]
AFS securities	40,137	28,278
Recurring Basis [Member]
AFS securities [Abstract]
AFS securities	1,576,030	1,348,698
Equity securities	33,013	30,737
Derivatives	71,481	108,779
Total	1,680,524	1,488,214
Liabilities [Abstract]
Derivatives	71,314	108,646
Total	71,314	108,646
Recurring Basis [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS securities	0	0
Equity securities	32,013	28,737
Derivatives	0	0
Total	32,013	28,737
Liabilities [Abstract]
Derivatives	0	0
Total	0	0
Recurring Basis [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS securities	1,576,030	1,348,698
Equity securities	1,000	2,000
Derivatives	71,481	108,779
Total	1,648,511	1,459,477
Liabilities [Abstract]
Derivatives	71,314	108,646
Total	71,314	108,646
Recurring Basis [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS securities	0	0
Equity securities	0	0
Derivatives	0	0
Total	0	0
Liabilities [Abstract]
Derivatives	0	0
Total	0	0
Recurring Basis [Member] \| Federal Agency [Member]
AFS securities [Abstract]
AFS securities	242,966	243,597
Recurring Basis [Member] \| Federal Agency [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] \| Federal Agency [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS securities	242,966	243,597
Recurring Basis [Member] \| Federal Agency [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] \| State & Municipal [Member]
AFS securities [Abstract]
AFS securities	84,021	43,180
Recurring Basis [Member] \| State & Municipal [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] \| State & Municipal [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS securities	84,021	43,180
Recurring Basis [Member] \| State & Municipal [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] \| Mortgage-Backed [Member]
AFS securities [Abstract]
AFS securities	650,195	595,839
Recurring Basis [Member] \| Mortgage-Backed [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] \| Mortgage-Backed [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS securities	650,195	595,839
Recurring Basis [Member] \| Mortgage-Backed [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] \| Collateralized Mortgage Obligations [Member]
AFS securities [Abstract]
AFS securities	558,711	437,804
Recurring Basis [Member] \| Collateralized Mortgage Obligations [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] \| Collateralized Mortgage Obligations [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS securities	558,711	437,804
Recurring Basis [Member] \| Collateralized Mortgage Obligations [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] \| Corporate [Member]
AFS securities [Abstract]
AFS securities	40,137	28,278
Recurring Basis [Member] \| Corporate [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] \| Corporate [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS securities	40,137	28,278
Recurring Basis [Member] \| Corporate [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS securities	$ 0	$ 0

The percentage of liquidation expenses estimated with liquidating impaired collateral.

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Amount of loans considered to be collateral dependent.

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Amount of specific reserves for loans considered to be collateral dependent.

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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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, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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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), classified as current.

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Fair value of financial and nonfinancial obligations.

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