Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) property	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jan. 01, 2019 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortization of above and below-market leases	$ 5,400,000	$ 4,700,000	$ 3,700,000
Remaining weighted average lease term related to these intangible assets and liabilities	7 years 9 months 18 days
Straight-line rent and accounts receivables, net of allowances	$ 32,500,000	27,400,000
Straight-line rent and accounts receivables, allowances	(900,000)	(200,000)
Deferred financing cost accumulated amortization	9,400,000	8,300,000
Unrecognized tax benefits	0	0
Operating lease, liability	400,000
Operating lease, ROU asset	$ 400,000
Operating lease, weighted average remaining lease term			3 years 6 months
Operating lease, weighted average discount rate			2.70%
Number of reportable segments | property	1
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssets
Accounting Standards Update 2016-02
Accounts, Notes, Loans and Financing Receivable [Line Items]
Operating lease, liability				$ 900,000
Operating lease, ROU asset				$ 800,000
Senior Secured Loan Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impairment charges	$ 0	$ 0