Investments Cash Distributions from Equity Method Investments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Proceeds from Equity Method Investment, Cash Distributions	$ 38,141	$ 36,258	$ 149,650	$ 125,604