Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands							6 Months Ended	12 Months Ended
	May. 13, 2016	Feb. 12, 2016	Nov. 13, 2015	Aug. 14, 2015	May. 15, 2015	Feb. 13, 2015	Jun. 30, 2016	Dec. 31, 2015
Subsequent Event [Line Items]
Cash distribution per unit		$ 0.785	$ 0.7625	$ 0.7400	$ 0.7175	$ 0.6950		$ 2.915
Total cash distributions		$ 178,808	$ 173,413	$ 168,296	$ 163,178	$ 158,061		$ 662,948
Scenario, Forecast
Subsequent Event [Line Items]
Cash distribution per unit	$ 0.8025						$ 1.5875
Total cash distributions	$ 182,797						$ 361,605