Debt - Schedule of Debt (Details)	3 Months Ended
	Mar. 31, 2017 USD ($) note_payable	Dec. 30, 2016 USD ($)
Debt [Roll Forward]
Total debt, Beginning balance	$ 6,367,248,000
Debt Issuances, Net	2,403,000
Repayments, Extinguishment and Assumptions, Net	(84,091,000)
Accretion and Amortization	1,843,000
Total debt, Ending balance	6,287,403,000
Mortgages and Other Debt [Member]
Debt [Roll Forward]
Total debt, Beginning balance	2,671,106,000
Debt Issuances, Net	2,403,000
Repayments, Extinguishment and Assumptions, Net	(84,091,000)
Accretion and Amortization	(2,501,000)
Total debt, Ending balance	2,586,917,000
Mortgage Notes Payable [Member]
Debt [Roll Forward]
Outstanding balance, Beginning balance	2,629,949,000
Net premiums (discount), Beginning balance	36,751,000
Deferred costs, Beginning balance	(16,633,000)
Debt Issuances	2,403,000
Repayments, Extinguishment and Assumptions	(78,966,000)
Accretion and Amortization, (Premiums) Discount	(3,290,000)
Accretion and Amortization, Deferred costs	817,000
Outstanding balance, Ending balance	2,553,386,000
Net premiums (discount), Ending balance	33,461,000
Deferred costs, Ending balance	(15,816,000)
Mortgage notes in connection with default from non-recourse loan	$ 41,800,000	$ 11,600,000
Number of mortgage notes payable in default | note_payable	2
Other Debt [Member]
Debt [Roll Forward]
Outstanding balance, Beginning balance	$ 20,947,000
Net premiums (discount), Beginning balance	92,000
Repayments, Extinguishment and Assumptions	(5,125,000)
Accretion and Amortization, (Premiums) Discount	(28,000)
Outstanding balance, Ending balance	15,822,000
Net premiums (discount), Ending balance	64,000
Corporate Bonds [Member]
Debt [Roll Forward]
Outstanding balance, Beginning balance	2,250,000,000
Net premiums (discount), Beginning balance	(1,937,000)
Deferred costs, Beginning balance	(21,839,000)
Total debt, Beginning balance	2,226,224,000
Accretion and Amortization, (Premiums) Discount	176,000
Accretion and Amortization, Deferred costs	907,000
Accretion and Amortization	1,083,000
Outstanding balance, Ending balance	2,250,000,000
Net premiums (discount), Ending balance	(1,761,000)
Deferred costs, Ending balance	(20,932,000)
Total debt, Ending balance	2,227,307,000
Convertible Debt [Member]
Debt [Roll Forward]
Outstanding balance, Beginning balance	1,000,000,000
Net premiums (discount), Beginning balance	(12,894,000)
Deferred costs, Beginning balance	(13,766,000)
Total debt, Beginning balance	973,340,000
Accretion and Amortization, (Premiums) Discount	1,261,000
Accretion and Amortization, Deferred costs	1,430,000
Accretion and Amortization	2,691,000
Outstanding balance, Ending balance	1,000,000,000
Net premiums (discount), Ending balance	(11,633,000)
Deferred costs, Ending balance	(12,336,000)
Total debt, Ending balance	976,031,000
Credit Facility [Member]
Debt [Roll Forward]
Outstanding balance, Beginning balance	500,000,000
Deferred costs, Beginning balance	(3,422,000)
Total debt, Beginning balance	496,578,000
Accretion and Amortization, Deferred costs	570,000
Accretion and Amortization	570,000
Outstanding balance, Ending balance	500,000,000
Deferred costs, Ending balance	(2,852,000)
Total debt, Ending balance	$ 497,148,000