Fair value measurements (Details) - Recurring - USD ($) $ in Thousands |
May. 30, 2015 |
Feb. 28, 2015 |
May. 31, 2014 |
|---|---|---|---|
| Assets | |||
| Total assets | $ 4,480 | $ 4,437 | $ 3,555 |
| Liabilities | |||
| Total liabilities | 4,470 | 4,281 | 3,563 |
| Level 2 | Other current assets | |||
| Assets | |||
| Nonqualified retirement plan | 4,086 | 3,951 | 3,555 |
| Foreign currency forward contracts | 394 | 486 | |
| Level 2 | Accrued liabilities | |||
| Liabilities | |||
| Nonqualified retirement plan | 4,094 | 3,966 | $ 3,563 |
| Foreign currency hedge instruments | $ 376 | $ 315 |