Debt - Components of Debt (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Outstanding Principal	$ 7,165,859	$ 5,662,816
Fixed Rate
Debt Instrument [Line Items]
Outstanding Principal	2,848,149	1,208,934
Variable Rate
Debt Instrument [Line Items]
Outstanding Principal	$ 4,317,710	4,453,882
5.375% Exchangeable Senior Notes | Convertible and Exchangeable Senior Notes
Debt Instrument [Line Items]
Interest Rate	5.375%
Recourse
Debt Instrument [Line Items]
Outstanding Principal	$ 858,612	931,294
Recourse | Fixed Rate
Debt Instrument [Line Items]
Outstanding Principal	578,495	651,177
Recourse | Variable Rate
Debt Instrument [Line Items]
Outstanding Principal	280,117	280,117
Recourse | Corporate credit facility
Debt Instrument [Line Items]
Outstanding Principal	$ 0	$ 0
Weighted Average Years Remaining to Maturity	1 year 3 months 18 days	2 years
Recourse | Corporate credit facility | Fixed Rate
Debt Instrument [Line Items]
Outstanding Principal	$ 0	$ 0
Recourse | Corporate credit facility | Variable Rate
Debt Instrument [Line Items]
Outstanding Principal	$ 0	$ 0
Weighted Average Years Remaining to Maturity	1 year 3 months 18 days	2 years
Recourse | Convertible and Exchangeable Senior Notes
Debt Instrument [Line Items]
Outstanding Principal	$ 545,107	$ 616,105
Weighted Average Interest Rate (Per Annum) (percent)	5.36%	4.27%
Weighted Average Years Remaining to Maturity	3 years 10 months 24 days	2 years
Recourse | Convertible and Exchangeable Senior Notes | Fixed Rate
Debt Instrument [Line Items]
Outstanding Principal	$ 545,107	$ 616,105
Weighted Average Interest Rate (Per Annum) (percent)	5.36%	4.27%
Weighted Average Years Remaining to Maturity	3 years 10 months 24 days	2 years
Recourse | Convertible and Exchangeable Senior Notes | Variable Rate
Debt Instrument [Line Items]
Outstanding Principal	$ 0	$ 0
Recourse | Secured debt
Debt Instrument [Line Items]
Outstanding Principal	$ 33,388	$ 35,072
Weighted Average Interest Rate (Per Annum) (percent)	5.02%	5.02%
Weighted Average Years Remaining to Maturity	5 years 2 months 12 days	5 years 10 months 24 days
Recourse | Secured debt | Fixed Rate
Debt Instrument [Line Items]
Outstanding Principal	$ 33,388	$ 35,072
Weighted Average Interest Rate (Per Annum) (percent)	5.02%	5.02%
Weighted Average Years Remaining to Maturity	5 years 2 months 12 days	5 years 10 months 24 days
Recourse | Secured debt | Variable Rate
Debt Instrument [Line Items]
Outstanding Principal	$ 0	$ 0
Recourse-NRF | Junior subordinated debt (2)
Debt Instrument [Line Items]
Outstanding Principal	$ 280,117	$ 280,117
Weighted Average Interest Rate (Per Annum) (percent)	3.10%	4.77%
Weighted Average Years Remaining to Maturity	15 years 8 months 12 days	16 years 4 months 24 days
Recourse-NRF | Junior subordinated debt (2) | Fixed Rate
Debt Instrument [Line Items]
Outstanding Principal	$ 0	$ 0
Recourse-NRF | Junior subordinated debt (2) | Variable Rate
Debt Instrument [Line Items]
Outstanding Principal	$ 280,117	$ 280,117
Weighted Average Interest Rate (Per Annum) (percent)	3.10%	4.77%
Weighted Average Years Remaining to Maturity	15 years 8 months 12 days	16 years 4 months 24 days
Non-recourse
Debt Instrument [Line Items]
Outstanding Principal	$ 6,307,247	$ 4,731,522
Non-recourse | Wellness Infrastructure
Debt Instrument [Line Items]
Carrying value of defaulted debt	45,000
Non-recourse | Healthcare And Other Equity And Debt
Debt Instrument [Line Items]
Carrying value of defaulted debt		235,600
Non-recourse | Other
Debt Instrument [Line Items]
Carrying value of defaulted debt	114,000
Notices of acceleration, amount	21,300
Non-recourse | Fixed Rate
Debt Instrument [Line Items]
Outstanding Principal	2,269,654	557,757
Non-recourse | Variable Rate
Debt Instrument [Line Items]
Outstanding Principal	4,037,593	4,173,765
Non-recourse | Secured debt | Wellness Infrastructure
Debt Instrument [Line Items]
Outstanding Principal	$ 2,773,688	$ 2,953,706
Weighted Average Interest Rate (Per Annum) (percent)	4.08%	5.13%
Weighted Average Years Remaining to Maturity	3 years 9 months 18 days	4 years 4 months 24 days
Non-recourse | Secured debt | Digital Operating
Debt Instrument [Line Items]
Outstanding Principal	$ 2,546,359	$ 539,155
Weighted Average Interest Rate (Per Annum) (percent)	4.15%	6.98%
Weighted Average Years Remaining to Maturity	3 years 3 months 18 days	4 years 9 months 18 days
Non-recourse | Secured debt | Other
Debt Instrument [Line Items]
Outstanding Principal	$ 987,200	$ 1,238,661
Weighted Average Interest Rate (Per Annum) (percent)	3.17%	3.37%
Weighted Average Years Remaining to Maturity	2 years 3 months 18 days	2 years 8 months 12 days
Non-recourse | Secured debt | Fixed Rate | Wellness Infrastructure
Debt Instrument [Line Items]
Outstanding Principal	$ 403,490	$ 405,980
Weighted Average Interest Rate (Per Annum) (percent)	4.55%	4.55%
Weighted Average Years Remaining to Maturity	4 years 4 months 24 days	5 years 1 month 6 days
Non-recourse | Secured debt | Fixed Rate | Digital Operating
Debt Instrument [Line Items]
Outstanding Principal	$ 1,711,314	$ 0
Weighted Average Interest Rate (Per Annum) (percent)	3.89%
Weighted Average Years Remaining to Maturity	3 years
Non-recourse | Secured debt | Fixed Rate | Other
Debt Instrument [Line Items]
Outstanding Principal	$ 154,850	$ 151,777
Weighted Average Interest Rate (Per Annum) (percent)	4.20%	4.26%
Weighted Average Years Remaining to Maturity	2 years 7 months 6 days	3 years 4 months 24 days
Non-recourse | Secured debt | Variable Rate | Wellness Infrastructure
Debt Instrument [Line Items]
Outstanding Principal	$ 2,370,198	$ 2,547,726
Weighted Average Interest Rate (Per Annum) (percent)	4.00%	5.22%
Weighted Average Years Remaining to Maturity	3 years 8 months 12 days	4 years 3 months 18 days
Non-recourse | Secured debt | Variable Rate | Digital Operating
Debt Instrument [Line Items]
Outstanding Principal	$ 835,045	$ 539,155
Weighted Average Interest Rate (Per Annum) (percent)	4.67%	6.98%
Weighted Average Years Remaining to Maturity	3 years 9 months 18 days	4 years 9 months 18 days
Non-recourse | Secured debt | Variable Rate | Other
Debt Instrument [Line Items]
Outstanding Principal	$ 832,350	$ 1,086,884
Weighted Average Interest Rate (Per Annum) (percent)	2.97%	3.24%
Weighted Average Years Remaining to Maturity	2 years 2 months 12 days	2 years 7 months 6 days