XML 54 R43.htm IDEA: XBRL DOCUMENT
v3.20.2

LOANS AND ALLOWANCE FOR CREDIT LOSSES - Summary of Loan Portfolio by Type of Loan (Details) (Parenthetical) - USD ($) $ in Millions | Jun. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Receivables [Abstract] |  |
Accrued interest receivable on loans | $ 8.9 | $ 6.4

X
- Definition Financing receivable accrued interest. + References No definition available. + Details
Name: | gnty_FinancingReceivableAccruedInterest
Namespace Prefix: | gnty_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_ReceivablesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration