Partners' Capital and Distributions (Distributions) (Details) - USD ($) $ / shares in Units, $ in Thousands |
12 Months Ended | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Nov. 14, 2018 |
Aug. 14, 2018 |
May 15, 2018 |
Feb. 14, 2018 |
Nov. 14, 2017 |
Aug. 14, 2017 |
May 15, 2017 |
Feb. 14, 2017 |
Nov. 14, 2016 |
Aug. 12, 2016 |
May 13, 2016 |
Feb. 12, 2016 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Partners' Capital Notes [Abstract] | |||||||||||||||
| Partners' Capital Account, Distribution Per Unit of Limited Partner Interest (in dollars per share) | $ 0.9775 | $ 0.9575 | $ 0.9375 | $ 0.9200 | $ 0.9050 | $ 0.8900 | $ 0.8725 | $ 0.8550 | $ 0.83750 | $ 0.8200 | $ 0.8025 | $ 0.7850 | $ 3.7925 | $ 3.5225 | $ 3.245 |
| Limited Partners' Capital Account, Distribution Amount | $ 223,061 | $ 218,497 | $ 213,933 | $ 209,940 | $ 206,362 | $ 202,942 | $ 198,951 | $ 194,961 | $ 190,769 | $ 186,783 | $ 182,797 | $ 178,808 | $ 865,431 | $ 803,216 | $ 739,157 |