Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) segment derivative_instrument	Dec. 31, 2018 USD ($) derivative_instrument	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)
Accounting Policies [Abstract]
Property impairment charges	$ 0	$ 0	$ 0
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortization of above and below-market leases	$ 4,700,000	3,700,000	$ 2,200,000
Remaining weighted average lease term related to these intangible assets and liabilities	8 years
Straight-line rent and accounts receivables, net of allowances	$ 27,400,000	25,700,000
Straight-line rent and accounts receivables, allowances	200,000	200,000
Deferred financing cost accumulated amortization	8,300,000	6,900,000
Unrecognized tax benefits	$ 0	0
Performance measurement period	3 years
Derivative [Line Items]
Interest rate cap notional value	$ 100,000,000.0
Interest rate cap fair value	0	25,000
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, liability	600,000
Operating lease, ROU asset	$ 600,000
Number of reportable segments | segment	1
Interest rate cap [Member]
Derivative [Line Items]
Interest rate cap notional value	$ 100,000,000.0	$ 150,000,000.0
Derivative cap interest rate	4.00%	4.00%
Interest rate cap [Member] | Minimum [Member]
Derivative [Line Items]
Derivative, basis spread on variable rate	1.20%	1.20%
Interest rate cap [Member] | Maximum [Member]
Derivative [Line Items]
Derivative, basis spread on variable rate	1.70%	1.70%
Interest Rate Cap, Maturity 5/4/2021 [Member]
Derivative [Line Items]
Interest rate cap notional value	$ 50,000,000.0
Derivative cap interest rate	4.00%
Interest Rate Cap, Maturity 4/1/2019 [Member]
Derivative [Line Items]
Interest rate cap notional value	$ 50,000,000.0
Derivative cap interest rate	4.00%
Interest Rate Cap, Maturity 2/3/2020 [Member]
Derivative [Line Items]
Interest rate cap notional value	$ 50,000,000.0
Derivative cap interest rate	4.00%
Interest rate [Member] | Interest rate cap [Member] | Minimum [Member]
Derivative [Line Items]
Derivative, basis spread on variable rate	1.20%
Interest rate [Member] | Interest rate cap [Member] | Maximum [Member]
Derivative [Line Items]
Derivative, basis spread on variable rate	1.70%
Senior Secured Loan Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impairment charges	$ 0	$ 0
Cash flow hedging [Member] | Interest rate cap [Member]
Derivative [Line Items]
Number of interest rate cap transactions | derivative_instrument	2	3
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, liability				$ 900,000
Operating lease, ROU asset				$ 800,000
Operating lease, weighted average remaining lease term				3 years 6 months
Operating lease, weighted average discount rate				2.70%