Accumulated other comprehensive income loss

No definition available.

Name:	gnty_AccumulatedOtherComprehensiveIncomeLoss
Namespace Prefix:	gnty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Available for sale securities transferred to held to maturity.

+ References

No definition available.

+ Details

Name:	gnty_AvailableForSaleSecuritiesTransferredToHeldToMaturity
Namespace Prefix:	gnty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Available for sale securities transferred to held to maturity net of unrealized gain.

+ References

No definition available.

+ Details

Name:	gnty_AvailableForSaleSecuritiesTransferredToHeldToMaturityNetOfUnrealizedGain
Namespace Prefix:	gnty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Available for sale securities transferred to held to maturity, net of unrealized loss

+ References

No definition available.

+ Details

Name:	gnty_AvailableForSaleSecuritiesTransferredToHeldToMaturityNetOfUnrealizedLoss
Namespace Prefix:	gnty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt securities available for sale debt securities number of positions.

+ References

No definition available.

+ Details

Name:	gnty_DebtSecuritiesAvailableForSaleDebtSecuritiePositionNumberOfPositions
Namespace Prefix:	gnty_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Marketable Securities Pledged As Collateral

+ References

No definition available.

+ Details

Name:	gnty_MarketableSecuritiesPledgedAsCollateral
Namespace Prefix:	gnty_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of securities held amount greater than ten percentage of share holders equity.

+ References

No definition available.

+ Details

Name:	gnty_NumberOfSecuritiesHeldAmountGreaterThanTenPercentageOfShareHoldersEquity
Namespace Prefix:	gnty_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of unrealized loss exceeds book value.

+ References

No definition available.

+ Details

Name:	gnty_PercentageOfUnrealizedLossExceedsBookValue
Namespace Prefix:	gnty_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aaa)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481830/320-10-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleAndHeldToMaturity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-4

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

MARKETABLE SECURITIES - Narrative (Details)	3 Months Ended
MARKETABLE SECURITIES - Narrative (Details)	Mar. 31, 2025 USD ($) Security Position	Jun. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2024 USD ($)	Mar. 31, 2024 USD ($)
Investments, Debt and Equity Securities [Abstract]
Allowance for credit losses for available for sale debt securities	$ 0			$ 0
Number of investment in an unrealized loss position \| Position	257
Number of investment in an sale debt securities \| Position	92
Percentage of unrealized loss exceeds book value	20.00%
Number of securities other than agencies amount \| Security	0
Available for sale securities transferred to held to maturity, net of unrealized gain			$ 10,235,000
Available for sale securities transferred to held to maturity		$ 106,157,000	$ 172,292,000
Available for sale securities transferred to held to maturity, net of unrealized loss		$ 13,186,000
Fair value of securities pledged as collateral	$ 304,821,000			316,120,000
Number of available for sale held to maturity securities sold	0				$ 0
Accumulated other comprehensive income (loss)	$ (7,588,000)			$ (7,498,000)