Dispositions and Assets Held for Sale - Summary of Real Property Disposition Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Real estate dispositions:
Total dispositions	$ 528,448	$ 436,071
Gain (loss) on real estate dispositions, net	262,824	167,409
Net other assets/liabilities disposed	10,120	(748)
Proceeds from real estate dispositions	801,392	602,732
Triple-net
Real estate dispositions:
Total dispositions	33,445	436,071
Outpatient Medical
Real estate dispositions:
Total dispositions	$ 495,003	$ 0