Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands |
6 Months Ended | 9 Months Ended | 12 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Aug. 14, 2019 |
May 15, 2019 |
Feb. 14, 2019 |
Nov. 14, 2018 |
Aug. 14, 2018 |
May 15, 2018 |
Feb. 14, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
Sep. 30, 2019 |
Dec. 31, 2018 |
|
| Subsequent Event [Line Items] | |||||||||||
| Cash distribution per unit (in dollars per share) | $ 1.0050 | $ 0.9975 | $ 0.9775 | $ 0.9575 | $ 0.9375 | $ 0.9200 | $ 2.0025 | $ 1.8575 | $ 3.7925 | ||
| Total cash distributions | $ 229,545 | $ 227,832 | $ 223,061 | $ 218,497 | $ 213,933 | $ 209,940 | $ 457,377 | $ 423,873 | $ 865,431 | ||
| Scenario, Forecast | |||||||||||
| Subsequent Event [Line Items] | |||||||||||
| Cash distribution per unit (in dollars per share) | $ 1.0125 | $ 3.0150 | |||||||||
| Total cash distributions | $ 231,258 | $ 688,635 | |||||||||