Summary of Significant Accounting Policies - Narrative (Details)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	May 31, 2019 USD ($) property	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) property	Jun. 30, 2018 USD ($)	Dec. 31, 2018 property
Property, Plant and Equipment [Line Items]
Impairment loss		$ 10,146,000	$ 2,456,000	$ 10,146,000	$ 5,239,000
Variable Interest Entities
VIE carrying value		288,900,000		288,900,000
Finance Lease Obligations
Finance leases for equipment		$ 3,200,000		3,200,000
Payments of finance lease obligations				$ 300,000
Payments of capital lease obligations					294,000
Weighted average interest rate (percent)		5.80%		5.80%
Remaining lease term (years)		3 years 4 months 24 days		3 years 4 months 24 days
Acquisition Fees and Expenses
Acquisition fee and expense cap		6.00%		6.00%
Credit Losses and Impairment on Investments
Impairment loss				$ 10,100,000	5,200,000
Period past due for suspension of income recognition (in days)				90 days
Investments in Unconsolidated Ventures
Impairment recognized				$ 0
Income Taxes
Deferred tax asset		$ 12,200,000		12,200,000
Income tax expense		15,000	15,000	21,000	30,000
Variable lease revenues		4,100,000	$ 3,900,000	$ 8,100,000	$ 8,200,000
Peregrine
Finance Lease Obligations
Number of properties held for sale | property				1		1
Number of properties sold | property	2
Proceeds from sale of held-for-sale property	$ 19,700,000
Variable Interest Entity, Primary Beneficiary | Operating Real Estate
Variable Interest Entities
Assets of consolidated VIEs		600,000,000		$ 600,000,000
Variable Interest Entity, Primary Beneficiary | Mortgage Notes Payable
Variable Interest Entities
Liabilities of consolidated VIEs		$ 465,000,000		465,000,000
Real Estate | Rochester
Credit Losses and Impairment on Investments
Impairment loss				10,000,000
Held-for-sale
Credit Losses and Impairment on Investments
Impairment loss				$ 100,000