Corporate debt, Breakdown of corporate debt (Details) $ in Thousands, € in Millions |
6 Months Ended | ||
|---|---|---|---|
|
Feb. 10, 2017
EUR (€)
Swap
|
Jun. 30, 2018
USD ($)
|
Dec. 31, 2017
USD ($)
|
|
| Corporate debt [Abstract] | |||
| Non-current | $ 624,163 | $ 574,176 | |
| Current | 14,878 | 68,907 | |
| Total Corporate Debt | 639,041 | $ 643,083 | |
| Note Issuance Facility [Member] | |||
| Corporate debt [Abstract] | |||
| Total Corporate Debt | $ 312,808 | ||
| Principal amount | € | € 275 | ||
| Number of interest rate swaps | Swap | 2 | ||
| Fixed interest rate | 5.50% | ||
| Note Issuance Facility [Member] | EURIBOR [Member] | |||
| Corporate debt [Abstract] | |||
| Adjustment to interest rate | 4.90% | ||
| Series 1 Notes [Member] | |||
| Corporate debt [Abstract] | |||
| Maturity date | 2022 | ||
| Series 2 Notes [Member] | |||
| Corporate debt [Abstract] | |||
| Maturity date | 2023 | ||
| Series 3 Notes [Member] | |||
| Corporate debt [Abstract] | |||
| Maturity date | 2024 |