Variable Interest Entities and Noncontrolling Interests - Income or loss attributable to third party investors (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Noncontrolling Interest [Abstract]
Amounts attributable to non-redeemable noncontrolling interests	$ (9,346)	$ (33,716)	$ (25,670)	$ (49,958)
Dividends attributable to redeemable noncontrolling interests	(4,586)	(4,586)	(9,170)	(9,173)
Net (income) loss attributable to noncontrolling interests	$ (13,932)	$ (38,302)	$ (34,840)	$ (59,131)