Investments Cash Distributions from Equity Method Investments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Schedule of Equity Method Investments [Line Items]
Proceeds from Equity Method Investment, Cash Distributions	$ 32,911	$ 17,953	$ 182,561	$ 143,557