| Document and Entity Information | Mar. 29, 2022 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001712923 |
| Current Fiscal Year End Date | --12-31 |
| Document Type | 8-K |
| Document Period End Date | Mar. 29, 2022 |
| Entity Registrant Name | GREENSKY, INC. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-38506 |
| Entity Tax Identification Number | 82-2135346 |
| Entity Address, Address Line One | 5565 Glenridge Connector |
| Entity Address, Address Line Two | Suite 700 |
| Entity Address, City or Town | Atlanta |
| Entity Address, State or Province | GA |
| Entity Address, Postal Zip Code | 30342 |
| City Area Code | (678) |
| Local Phone Number | 264-6105 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Class A common stock, $0.01 par value |
| Trading Symbol | GSKY |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
