Real Estate Investments, Net (Narrative) (Details) $ in Thousands									1 Months Ended	3 Months Ended				9 Months Ended	12 Months Ended
	Dec. 21, 2021 USD ($)	May 14, 2021 USD ($)	Jan. 15, 2021 USD ($) property	Dec. 16, 2020 USD ($)	Nov. 02, 2020 USD ($) property	Mar. 19, 2020 USD ($) property	Aug. 22, 2019 USD ($) property	Feb. 06, 2019 USD ($) property	Nov. 30, 2020 USD ($) property	Dec. 31, 2021 USD ($) property	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($) property	Jun. 30, 2019 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) property	Dec. 31, 2020 USD ($) property	Dec. 31, 2019 USD ($) property	Dec. 31, 2021 property	Dec. 31, 2021 encumbered_property	Apr. 30, 2021 USD ($)	Jan. 31, 2021 property	Jul. 01, 2020 property	Jun. 30, 2020 USD ($) property	Apr. 30, 2020 USD ($) property	Jan. 31, 2020 USD ($) property	Aug. 01, 2019 USD ($)	Apr. 01, 2019 USD ($)	Mar. 31, 2019 property	Mar. 21, 2019 USD ($)	Sep. 25, 2018 USD ($)	Jul. 26, 2018 USD ($)
Real Estate [Line Items]
Number of properties purchased | property															202
Payments to acquire property															$ 159,300	$ 94,984	$ 91,998
Gain (loss) on sale of real estate investments															3,648	5,230	8,790
Repayments of credit facility borrowings															298,804	26,091	368,300
Impairment charges											$ 6,100	$ 900			$ 40,951	36,446	55,969
Number of real estate properties																		202	113
LaSalle Tenant
Real Estate [Line Items]
Number of real estate properties | property																						4
Fannie Mae Master Credit Facilities
Real Estate [Line Items]
Repayments of credit facility borrowings									$ 4,200
Revolving Credit Facility
Real Estate [Line Items]
Repayments of credit facility borrowings				$ 17,600
Revolving Credit Facility | Credit Facilities
Real Estate [Line Items]
Repayments of debt																$ 4,400
Number of real estate properties | property																		92
Credit Facilities
Real Estate [Line Items]
Number of properties transferred | property					4											3
Credit Facilities | Fannie Mae Master Credit Facilities
Real Estate [Line Items]
Number of real estate properties | property																		21
Credit Facilities | Fannie Mae Master Credit Facilities | Capital One Facility
Real Estate [Line Items]
Repayments of debt																$ 4,200
Number of real estate properties | property																		11
Fannie Mae Master Credit Facility
Real Estate [Line Items]
Number of properties transferred | property					1
Unencumbered Properties
Real Estate [Line Items]
Number of properties transferred | property					2											1
Lutz, Florida | Fair Value | Valuation, Income Approach
Real Estate [Line Items]
Cash flows and capitalization rates															9.00%
Jupiter, Florida | Fair Value | Valuation, Income Approach
Real Estate [Line Items]
Cash flows and capitalization rates															7.00%
TEXAS
Real Estate [Line Items]
Impairment charges															$ 34,000
Wellington, Florida | Fair Value | Valuation, Income Approach
Real Estate [Line Items]
Cash flows and capitalization rates															9.00%
Disposed by sale
Real Estate [Line Items]
Contract sale price										$ 133,550					$ 133,550	$ 40,350	62,200
Gain (loss) on sale of real estate investments															3,648	5,230	8,790
Disposed by sale | TEXAS
Real Estate [Line Items]
Contract sale price										12,400					12,400
Disposed by sale | Hampton River Portfolio (two properties)
Real Estate [Line Items]
Number of properties disposed | property			2
Contract sale price	$ 37,800									37,800					37,800
Gain (loss) on sale of real estate investments	$ 1,323									$ 1,300
Disposed by sale | Wellington Green
Real Estate [Line Items]
Contract sale price		$ 30,750
Gain (loss) on sale of real estate investments		114									100
Impairment charges															900	2,300	9,900
Disposed by sale | NuVista Jupiter
Real Estate [Line Items]
Contract sale price		65,000
Gain (loss) on sale of real estate investments		$ 2,383									$ 2,400
Impairment charges																14,600	19,800
Disposed by sale | New York Six MOBs (five properties)
Real Estate [Line Items]
Contract sale price								$ 45,000
Gain (loss) on sale of real estate investments								$ 6,059
Disposed by sale | New York Six MOBs (one property)
Real Estate [Line Items]
Contract sale price							$ 13,600
Gain (loss) on sale of real estate investments							$ 2,883
Assets held for sale
Real Estate [Line Items]
Impairment charges															0	19,570	$ 22,634
Assets held for sale | Jupiter, Florida
Real Estate [Line Items]
Number of properties held for sale | property																	3
Assets held for use
Real Estate [Line Items]
Impairment charges															$ 40,951	$ 16,876	$ 33,335
Multi-tenant MOB
Real Estate [Line Items]
Number of properties purchased | property															5
Single Tenant MOB
Real Estate [Line Items]
Number of properties purchased | property															12
Medical Office Buildings
Real Estate [Line Items]
Payments to acquire property															$ 160,200
Medical Office Buildings | Discontinued Operations, Disposed of by Sale
Real Estate [Line Items]
Number of properties disposed | property										2
Medical Office Buildings | Disposed by sale
Real Estate [Line Items]
Contract sale price						$ 8,600
Gain (loss) on sale of real estate investments						$ 2,306
Medical Office Buildings | Disposed by sale | New York Six MOBs (five properties)
Real Estate [Line Items]
Number of properties disposed | property							1	5
Contract sale price																														$ 58,800	$ 68,000
Medical Office Buildings | Assets held for sale
Real Estate [Line Items]
Number of properties disposed | property						1
Seniors Housing Communities
Real Estate [Line Items]
Escrow deposits					$ 800
Impairment charges													$ 19
Seniors Housing Communities | Michigan
Real Estate [Line Items]
Gain (loss) on sale of real estate investments															$ (200)
Escrow deposits												$ 800
Seniors Housing Communities | Disposed by sale | Michigan
Real Estate [Line Items]
Number of properties disposed | property			4		7
Contract sale price			$ 0		$ 11,750
Gain (loss) on sale of real estate investments			$ (172)		$ (908)
Number of properties held for sale | property									11							11		11
Impairment charges																$ 19,600	$ 22,600
Seniors Housing Communities | Assets held for sale
Real Estate [Line Items]
Contract sale price																									$ 71,800	$ 200	$ 3,500		$ 3,600
Number of properties held for sale | property																								11				1
Non-refundable deposits																								$ 300	$ 1,000
Seniors Housing Communities | Assets held for sale | Michigan
Real Estate [Line Items]
Number of properties disposed | property					11
Contract sale price					$ 11,800
Number of properties held for sale | property												4				4									14
Number of properties transferred | property					7													7
Seniors Housing Communities | Assets held for sale | Wellington, Florida
Real Estate [Line Items]
Contract sale price																				$ 30,700
Seniors Housing Communities | Assets held for use
Real Estate [Line Items]
Number of properties held for sale | property																					3
Accumulated depreciation														$ 700
Skilled Nursing Facilities | Florida
Real Estate [Line Items]
Number of properties held for sale | property																	2
Skilled Nursing Facilities | Disposed by sale | Lutz, Florida
Real Estate [Line Items]
Contract sale price				20,000
Gain (loss) on sale of real estate investments				$ 3,832
Impairment charges																	$ 3,600
Skilled Nursing Facilities | Assets held for sale | Florida
Real Estate [Line Items]
Number of properties held for sale | property																							2
Wellington, Florida | Assets held for sale | Skilled Nursing Facilities
Real Estate [Line Items]
Prospective consideration																							$ 33,000
Assets held for sale | Jupiter, Florida
Real Estate [Line Items]
Prospective consideration																							65,000
Lutz, Florida | Assets held for sale | Skilled Nursing Facilities
Real Estate [Line Items]
Prospective consideration																							$ 20,000