Derivative financial instruments (Details) - USD ($) $ in Thousands |
9 Months Ended | ||
|---|---|---|---|
Sep. 30, 2018 |
Sep. 30, 2017 |
Dec. 31, 2017 |
|
| Breakdown of fair value amount of derivative financial instruments [Abstract] | |||
| Loss on cash flow hedges | $ 51,049 | $ 54,446 | |
| Interest Rate Derivatives [Member] | Euros [Member] | |||
| Breakdown of fair value amount of derivative financial instruments [Abstract] | |||
| Percent of notional amount of debt hedged in next 12 months | 100.00% | ||
| Percentage of notional amount of debt hedged in year two | 75.00% | ||
| Interest Rate Derivatives [Member] | Cash Flow Hedge [Member] | |||
| Breakdown of fair value amount of derivative financial instruments [Abstract] | |||
| Assets | $ 15,350 | $ 8,230 | |
| Liabilities | 266,884 | 329,731 | |
| Loss on cash flow hedges | (51,049) | $ (54,446) | |
| After-tax result accumulated in equity | $ 105,959 | $ 80,968 | |