| Component: (Network and Table) | |
|---|---|
| Network | 076 - Disclosure - Note 11 - Commitments and Contingencies (Details) - Changes to Environmental Liabilities (http://www.unifirst.com/role/ChangestoEnvironmentalLiabilitiesTable) |
| Table | (Implied) |
| Reporting Entity [Axis] | 0000717954 (http://www.sec.gov/CIK) |
| Changes to Environmental Liabilities [Abstract] | Period [Axis] | |
|---|---|---|
2012-08-26 - 2013-08-31 | 2011-08-28 - 2012-08-25 | |
Changes to Environmental Liabilities [Abstract] | ||
Balance | 20,020,000 | 18,368,000 |
Costs incurred for which reserves have been provided | (1,862,000) | (1,277,000) |
Insurance proceeds received | 282,000 | 209,000 |
Interest accretion | 542,000 | 631,000 |
Changes in discount rates | (1,585,000) | 1,346,000 |
Revisions in estimates | 2,283,000 | 743,000 |
Balance | 19,680,000 | 20,020,000 |