Property and equipment (Details) - USD ($) $ in Thousands |
Mar. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Property and equipment | ||
| Total property and equipment | $ 358,686 | $ 337,888 |
| Less: accumulated depreciation and amortization | (133,724) | (123,388) |
| Total property and equipment, net | 224,962 | 214,500 |
| Leasehold improvements | ||
| Property and equipment | ||
| Total property and equipment | 272,139 | 243,743 |
| Construction in progress | ||
| Property and equipment | ||
| Total property and equipment | 48,383 | 57,692 |
| Software | ||
| Property and equipment | ||
| Total property and equipment | 25,887 | 24,349 |
| Computer equipment | ||
| Property and equipment | ||
| Total property and equipment | 10,526 | 10,366 |
| Furniture, fixtures and office equipment | ||
| Property and equipment | ||
| Total property and equipment | $ 1,751 | $ 1,738 |