Credit Concentration (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($) property	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) property	Sep. 30, 2019 USD ($)	Dec. 31, 2019
Concentration Risk [Line Items]
Total NOI	$ 402,157	$ 610,545	$ 1,506,689	$ 1,830,962
Percentage total investments with top five customers					37.00%
Net operating income
Concentration Risk [Line Items]
Number of Properties | property	1,488		1,488
Total NOI			$ 1,506,689
Percent of NOI			100.00%
Net operating income | Sunrise Senior Living
Concentration Risk [Line Items]
Number of Properties | property	165		165
Total NOI			$ 194,952
Percent of NOI			13.00%
Net operating income | ProMedica
Concentration Risk [Line Items]
Number of Properties | property	215		215
Total NOI			$ 159,562
Percent of NOI			11.00%
Net operating income | Revera
Concentration Risk [Line Items]
Number of Properties | property	94		94
Total NOI			$ 81,317
Percent of NOI			5.00%
Net operating income | Avery Healthcare
Concentration Risk [Line Items]
Number of Properties | property	59		59
Total NOI			$ 56,192
Percent of NOI			4.00%
Net operating income | Sagora Senior Living
Concentration Risk [Line Items]
Number of Properties | property	31		31
Total NOI			$ 50,539
Percent of NOI			3.00%
Net operating income | Remaining portfolio
Concentration Risk [Line Items]
Number of Properties | property	924		924
Total NOI			$ 964,127
Percent of NOI			64.00%