Property and equipment (Details) - USD ($) $ in Thousands |
Sep. 30, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Property and equipment | ||
| Total property and equipment | $ 306,184 | $ 198,764 |
| Less: accumulated depreciation and amortization | (113,275) | (86,992) |
| Total property and equipment, net | 192,909 | 111,772 |
| Leasehold improvements | ||
| Property and equipment | ||
| Total property and equipment | 194,344 | 152,627 |
| Construction in progress | ||
| Property and equipment | ||
| Total property and equipment | 76,574 | 20,104 |
| Computer equipment | ||
| Property and equipment | ||
| Total property and equipment | 11,285 | 7,909 |
| Software | ||
| Property and equipment | ||
| Total property and equipment | 22,210 | 17,827 |
| Furniture, fixtures and office equipment | ||
| Property and equipment | ||
| Total property and equipment | $ 1,771 | $ 297 |