Interest rate hedge agreements Outstanding interest rate swap (Details) $ in Thousands |
Mar. 31, 2018
USD ($)
contract
|
|---|---|
| Interest rate hedge agreements | |
| Fair Values | $ 6,461 |
| Notional Amount in Effect as of 3/31/18 | 600,000 |
| Notional Amount in Effect as of 12/31/18 | 600,000 |
| Notional Amount in Effect as of 12/31/19 | $ 100,000 |
| 1.16% Interest rate swap, effective March 29, 2018 | |
| Interest rate hedge agreements | |
| Number of Contracts | contract | 8 |
| Interest Pay Rate (as a percent) | 1.16% |
| Fair Values | $ 5,813 |
| Notional Amount in Effect as of 3/31/18 | 600,000 |
| Notional Amount in Effect as of 12/31/18 | 600,000 |
| Notional Amount in Effect as of 12/31/19 | $ 0 |
| 1.89% Interest rate swap, effective March 29, 2019 | |
| Interest rate hedge agreements | |
| Number of Contracts | contract | 1 |
| Interest Pay Rate (as a percent) | 1.89% |
| Fair Values | $ 648 |
| Notional Amount in Effect as of 3/31/18 | 0 |
| Notional Amount in Effect as of 12/31/18 | 0 |
| Notional Amount in Effect as of 12/31/19 | $ 100,000 |