| Document and Entity Information | Apr. 16, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Apr. 16, 2021 |
| Current Fiscal Year End Date | --12-31 |
| Entity Registrant Name | NIC Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 000-26621 |
| Entity Tax Identification Number | 52-2077581 |
| Entity Address, Address Line One | 25501 West Valley Parkway |
| Entity Address, Address Line Two | Suite 300 |
| Entity Address, City or Town | Olathe |
| Entity Address, State or Province | KS |
| Entity Address, Postal Zip Code | 66061 |
| City Area Code | 877 |
| Local Phone Number | 234-3468 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001065332 |
| Title of 12(b) Security | Common Stock, $0.0001 par value |
| Trading Symbol | EGOV |
| Security Exchange Name | NASDAQ |
