| Cover | Sep. 20, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Sep. 20, 2021 |
| Entity File Number | 001-37931 |
| Entity Registrant Name | GTY TECHNOLOGY HOLDINGS INC. |
| Entity Central Index Key | 0001682325 |
| Entity Tax Identification Number | 83-2860149 |
| Entity Incorporation, State or Country Code | MA |
| Entity Address, Address Line One | 1180 North Town Center Drive |
| Entity Address, Address Line Two | Suite 100 |
| Entity Address, City or Town | Las Vegas |
| Entity Address, State or Province | NV |
| Entity Address, Postal Zip Code | 89144 |
| City Area Code | 702 |
| Local Phone Number | 945-2898 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.0001 per share |
| Trading Symbol | GTYH |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Elected Not To Use the Extended Transition Period | false |
