Segment Reporting (Reconciliation of Segment Activity) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total revenues	$ 94,469	$ 95,440	$ 96,287	$ 88,718	$ 91,820	$ 90,191	$ 90,957	$ 89,438	$ 374,914	$ 362,406	$ 311,173
Property operating and maintenance									234,185
Property operating and maintenance										220,997	186,277
NOI									140,729	141,409	124,896
Impairment charges									(55,969)	(20,655)	(18,993)
Operating fees to related parties									(23,414)	(23,071)	(22,257)
Acquisition and transaction related									(362)	(302)	(2,986)
General and administrative									(20,530)	(17,275)	(15,673)
Depreciation and amortization									(81,032)	(83,212)	(77,641)
Gain (loss) on sale of real estate investments									8,790	(70)	438
Interest expense									(56,059)	(49,471)	(30,264)
Interest and other income									7	23	306
Loss on non-designated derivatives									(68)	(157)	(198)
Gain on acquisition									0	0	307
Income tax expense									(399)	(197)	(647)
Net loss attributable to non-controlling interests									393	216	164
Preferred stock dividends									(173)	0	0
Net loss attributable to common stockholders	$ (48,133)	$ (28,789)	$ (6,054)	$ (5,111)	$ (10,241)	$ (29,607)	$ (6,950)	$ (5,991)	(88,087)	(52,762)	(42,548)
Medical Office Buildings
Segment Reporting Information [Line Items]
Total revenues									100,379	99,103	82,850
Property operating and maintenance									31,813
Property operating and maintenance										30,295	24,137
NOI									68,566	68,808	58,713
Triple-Net Leased Healthcare Facilities
Segment Reporting Information [Line Items]
Total revenues									14,564	19,617	22,169
Property operating and maintenance									2,800
Property operating and maintenance										7,197	12,789
NOI									11,764	12,420	9,380
Seniors Housing Communities
Segment Reporting Information [Line Items]
Total revenues									259,971	243,686	206,154
Property operating and maintenance									199,572
Property operating and maintenance										183,505	149,351
NOI									$ 60,399	$ 60,181	$ 56,803