XML 47 R36.htm IDEA: XBRL DOCUMENT
v3.10.0.1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Mar. 31, 2018 USD ($) | Sep. 30, 2018 USD ($) subsidary
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income |  | $ 0
Retained Earnings |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income | $ 486 | $ 486
The Bank |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Number of wholly-owned non-bank subsidiaries | subsidary |  | 6

X
- Definition Number of Subsidiaries + References No definition available. + Details
Name: | gnty_NumberofSubsidiaries
Namespace Prefix: | gnty_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Tax Cuts And Jobs Act Of 2017, Reclassification From AOCI To Retained Earnings, Tax Effect + References No definition available. + Details
Name: | gnty_TaxCutsAndJobsActOf2017ReclassificationFromAOCIToRetainedEarningsTaxEffect
Namespace Prefix: | gnty_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_RetainedEarningsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ConsolidatedEntitiesAxis=srt_SubsidiariesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |