| Document and Entity Information | Jul. 01, 2020 |
| Cover [Abstract] | |
| Entity Registrant Name | MOBILE MINI INC |
| Amendment Flag | false |
| Entity Central Index Key | 0000911109 |
| Current Fiscal Year End Date | --12-31 |
| Document Type | 8-K |
| Document Period End Date | Jul. 1, 2020 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 1-12804 |
| Entity Tax Identification Number | 86-0748362 |
| Entity Address, Address Line One | 4646 E. Van Buren Street |
| Entity Address, Address Line Two | Suite 400 |
| Entity Address, City or Town | Phoenix |
| Entity Address, State or Province | AZ |
| Entity Address, Postal Zip Code | 85008 |
| City Area Code | (480) |
| Local Phone Number | 894-6311 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, $.01 par value |
| Trading Symbol | MINI |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
