| Note 6 - Leases - Balance Sheet Classification (Details) - USD ($) $ in Thousands | Sep. 30, 2020 | Jun. 30, 2020 | 
|---|---|---|
| Operating lease right of use assets | $ 70,018 | $ 71,465 | 
| Current operating lease liabilities | 9,695 | 9,535 | 
| Noncurrent operating lease liabilities | 65,694 | $ 67,248 | 
| Total operating lease liabilities | $ 75,389 | |
| Weighted average remaining lease term (in years): (Year) | 8 years 6 months 18 days | |
| Weighted average discount rate: | 4.38% | 
| X | ||||||||||
| 
- Definition Present value of lessee's discounted obligation for lease payments from operating lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
 | 
| X | ||||||||||
| 
- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as current. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
 | 
| X | ||||||||||
| 
- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
 | 
| X | ||||||||||
| 
- Definition Amount of lessee's right to use underlying asset under operating lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
 | 
| X | ||||||||||
| 
- Definition Weighted average discount rate for operating lease calculated at point in time. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
 | 
| X | ||||||||||
| 
- Definition Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/exampleRef 
 |