Investments Equity Method Investments Table (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Investments [Abstract]
Income on equity investments, net, before amortization of basis difference	$ 44,850	$ 33,609	$ 161,493	$ 139,808
Amortization of basis difference	(12,469)	(12,551)	(37,407)	(40,952)
Income on equity investments, net	$ 32,381	$ 21,058	$ 124,086	$ 98,856