Balance sheet components - Schedule of Property and Equipment, at cost (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Sep. 30, 2019 |
Sep. 30, 2018 |
Sep. 30, 2017 |
|
| Property and equipment, at cost | |||
| Property and equipment, gross | $ 329,636 | $ 273,212 | |
| Less: Accumulated depreciation and amortization | (230,047) | (195,668) | |
| Total property and equipment, net | 99,589 | 77,544 | |
| Fixed asset depreciation expense | 45,200 | 40,700 | $ 45,200 |
| Land | |||
| Property and equipment, at cost | |||
| Property and equipment, gross | 1,738 | 1,738 | |
| Building and improvements | |||
| Property and equipment, at cost | |||
| Property and equipment, gross | 12,044 | 12,044 | |
| Office furniture and equipment | |||
| Property and equipment, at cost | |||
| Property and equipment, gross | 246,671 | 203,512 | |
| Leasehold improvements | |||
| Property and equipment, at cost | |||
| Property and equipment, gross | $ 69,183 | $ 55,918 | |
| X | ||||||||||
- Definition Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|