Debt - Mortgage Notes Payable Narrative (Details) $ in Thousands				3 Months Ended		9 Months Ended
	Aug. 31, 2017 USD ($) property	Aug. 29, 2017 USD ($) property	Jun. 27, 2017 USD ($) property	Sep. 30, 2017 USD ($) note_payable	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) property note_payable	Sep. 30, 2016 USD ($)	Dec. 30, 2016 USD ($) property
Debt Instrument [Line Items]
Number of properties secured by each non-recourse loan | property			4			6
Gain (loss) on extinguishment and forgiveness of debt, net | $				$ 9,756	$ (2,003)	$ 18,691	$ (1,751)
Mortgage Notes Payable [Member]
Debt Instrument [Line Items]
Mortgage notes in connection with default from non-recourse loan | $	$ 41,600	$ 20,500	$ 38,300	$ 16,200		$ 16,200		$ 11,600
Number of mortgage notes payable in default | note_payable				1		1
Number of properties secured by each non-recourse loan | property	1	1
Gain (loss) on extinguishment and forgiveness of debt, net | $	$ 6,700	$ 4,800				$ 9,000
Number of non-recourse loan secured properties | property								16