Quarterly report pursuant to Section 13 or 15(d)

Partnership Equity and Distributions (Details)

v3.8.0.1
Partnership Equity and Distributions (Details)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Feb. 13, 2018
USD ($)
$ / shares
Nov. 17, 2017
USD ($)
Nov. 16, 2017
USD ($)
$ / shares
Aug. 16, 2017
USD ($)
$ / shares
May 10, 2017
USD ($)
$ / shares
Apr. 30, 2017
USD ($)
Feb. 08, 2017
USD ($)
$ / shares
Mar. 31, 2018
USD ($)
$ / shares
$ / item
Dec. 31, 2017
USD ($)
Partnership equity and distributions                  
Annual cash distribution (per unit)               0.68  
Minimum cash distributions to trigger unitholder and general partner distributions | $ / shares               $ 0.1955  
Distributions | $ $ 92,003 $ 1,392 $ 82,521 $ 75,023 $ 67,306 $ 75 $ 57,633 $ 92,003 $ 283,950
Distributions per limited partner unit (in dollars per share) | $ / shares $ 0.3650   $ 0.3400 $ 0.3200 $ 0.3000   $ 0.2800 $ 0.390  
General Partner                  
Partnership equity and distributions                  
Distributions | $ $ 23,772   $ 19,067 $ 15,328 $ 11,553   $ 7,543 $ 23,772 53,491
Common units                  
Partnership equity and distributions                  
Distributions | $ $ 68,231 $ 1,392 $ 63,454 $ 59,695 $ 55,753 $ 75 $ 50,090 $ 68,231 $ 230,459
Above $0.1955 up to $0.2125                  
Partnership equity and distributions                  
Unitholders marginal percentage interest in distribution               85.00%  
General Partners marginal percentage interest in distribution               15.00%  
Above $0.2125 up to $0.2550                  
Partnership equity and distributions                  
Unitholders marginal percentage interest in distribution               75.00%  
General Partners marginal percentage interest in distribution               25.00%  
Above $0.2550                  
Partnership equity and distributions                  
Unitholders marginal percentage interest in distribution               50.00%  
General Partners marginal percentage interest in distribution               50.00%  
Minimum                  
Partnership equity and distributions                  
Minimum quarterly cash distribution (per unit)               0.17  
Minimum | Above $0.1955 up to $0.2125                  
Partnership equity and distributions                  
Pro rata cash distribution to the holders of common and subordinate units               0.1955  
Minimum | Above $0.2125 up to $0.2550                  
Partnership equity and distributions                  
Pro rata cash distribution to the holders of common and subordinate units               0.2125  
Minimum | Above $0.2550                  
Partnership equity and distributions                  
Pro rata cash distribution to the holders of common and subordinate units               0.2550  
Maximum | Above $0.1955 up to $0.2125                  
Partnership equity and distributions                  
Pro rata cash distribution to the holders of common and subordinate units               0.2125  
Maximum | Above $0.2125 up to $0.2550                  
Partnership equity and distributions                  
Pro rata cash distribution to the holders of common and subordinate units               0.2550