Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands								6 Months Ended		9 Months Ended	12 Months Ended
	Aug. 14, 2017	May 15, 2017	Feb. 14, 2017	Nov. 14, 2016	Aug. 12, 2016	May 13, 2016	Feb. 12, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2017	Dec. 31, 2016
Subsequent Event [Line Items]
Cash distribution per unit		$ 0.8725	$ 0.8550	$ 0.8375	$ 0.8200	$ 0.8025	$ 0.785	$ 1.7275	$ 1.5875		$ 3.245
Total cash distributions		$ 198,951	$ 194,961	$ 190,769	$ 186,783	$ 182,797	$ 178,808	$ 393,912	$ 361,605		$ 739,157
Scenario, Forecast
Subsequent Event [Line Items]
Cash distribution per unit	$ 0.89									$ 2.6175
Total cash distributions	$ 202,942									$ 596,854