EQUITY AWARDS - Schedule of Stock Option Activity (Parenthetical) (Details)	6 Months Ended
Jun. 30, 2021
Share-Based Payment Arrangement [Abstract]
Stock dividend percentage	10.00%

Share Based Compensation Arrangement By Share Share based payment award options stock dividend percentage.

No definition available.

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