Real Estate Investments, Net (Acquired Assets) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) property	Dec. 31, 2018 USD ($) property	Dec. 31, 2017 USD ($) property
In-place leases
Real estate investments, at cost:
Weighted-average remaining amortization periods	8 years 1 month 6 days
Market lease and other intangible assets
Real estate investments, at cost:
Weighted-average remaining amortization periods	7 years
Business acquisitions
Real estate investments, at cost:
Land	$ 6,356	$ 14,417	$ 18,501
Buildings, fixtures and improvements	68,903	98,236	135,344
Development costs	5,721	8,591	11,952
Total tangible assets	80,980	121,244	165,797
Below-market lease liabilities	(1,483)	(286)	(888)
Total intangible assets and liabilities	11,018	6,812	23,130
Mortgage notes payable, net	0	0	(4,897)
Other liabilities assumed in the Asset Acquisition, net (2)	0	0	(1,056)
Cash paid for real estate investments, including acquisitions	$ 91,998	$ 128,056	$ 182,974
Number of properties purchased | property	9	14	23
Business acquisitions | In-place leases
Real estate investments, at cost:
In-place leases	$ 11,777	$ 6,823	$ 21,546
Business acquisitions | Market lease and other intangible assets
Real estate investments, at cost:
In-place leases	$ 724	$ 275	$ 2,472
American Realty Capital Healthcare Trust III
Real estate investments, at cost:
Number of properties purchased | property			19
Accounts payable and accrued expenses			$ (800)
Non-controlling interests			500
Deferred rent			100
Cash			200
Restricted cash			$ 200