EQUITY AWARDS - Schedule of Nonvested Stock Option Activity (Parenthetical) (Details)	9 Months Ended
Sep. 30, 2021
Share-Based Payment Arrangement [Abstract]
Stock dividend percentage	10.00%

Share based compensation arrangement by share based payment award nonvested options stock dividend percentage.

No definition available.

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