Consolidated Statements of Income (unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Supplemental information:
(b) Operating expenses – related party	$ 15,632	$ 15,083
(c) General and administrative expenses – related party	3,186	3,062
(d) Interest and debt expense – related party	$ 2,107	$ 1,566