| Cover | Mar. 01, 2023 |
| Document Information [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 01, 2023 |
| Entity File Number | 1-15371 |
| Entity Registrant Name | iStar Inc. |
| Entity Central Index Key | 0001095651 |
| Entity Tax Identification Number | 95-6881527 |
| Entity Incorporation, State or Country Code | MD |
| Entity Address, Address Line One | 1114 Avenue of the Americas |
| Entity Address, Address Line Two | 39th Floor |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10036 |
| City Area Code | 212 |
| Local Phone Number | 930-9400 |
| Written Communications | true |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | STAR |
| Security Exchange Name | NYSE |
| 8.00% Series D Cumulative Redeemable Preferred Stock, $0.001 par value | |
| Document Information [Line Items] | |
| Title of 12(b) Security | 8.00% Series D Cumulative Redeemable Preferred Stock, $0.001 par value |
| Trading Symbol | STAR-PD |
| Security Exchange Name | NYSE |
| 7.65% Series G Cumulative Redeemable Preferred Stock, $0.001 par value | |
| Document Information [Line Items] | |
| Title of 12(b) Security | 7.65% Series G Cumulative Redeemable Preferred Stock, $0.001 par value |
| Trading Symbol | STAR-PG |
| Security Exchange Name | NYSE |
| 7.50% Series I Cumulative Redeemable Preferred Stock, $0.001 par value | |
| Document Information [Line Items] | |
| Title of 12(b) Security | 7.50% Series I Cumulative Redeemable Preferred Stock, $0.001 par value |
| Trading Symbol | STAR-PI |
| Security Exchange Name | NYSE |
