Segment Reporting (Reconciliation of Segment Activity to Assets) (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Real estate investments, at cost:
Investments in real estate, net	$ 2,049,927,000	$ 2,108,948,000
Cash and cash equivalents	59,738,000	72,357,000	$ 95,691,000
Restricted cash	25,644,000	17,989,000
Assets held for sale	0	90,000
Derivative assets, at fair value	174,000	13,000
Straight-line rent receivable, net	23,858,000	23,322,000
Operating lease right-of-use assets	7,914,000	13,912,000
Prepaid expenses and other assets	32,564,000	34,932,000
Deferred costs, net	14,581,000	15,332,000
Total assets	2,214,400,000	2,286,895,000
Medical Office Buildings
Real estate investments, at cost:
Investments in real estate, net	1,149,241,000	1,121,898,000
Seniors Housing Communities
Real estate investments, at cost:
Investments in real estate, net	$ 900,686,000	$ 987,050,000