Summary of Significant Accounting Principles - Additional Information (Details)	3 Months Ended
	Mar. 31, 2019 USD ($) Loan Segment	Mar. 31, 2018 USD ($) Loan	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($) Loan
Summary Of Significant Accounting Policies [Line Items]
Percentage of ownership interests in operating partnership	75.20%			69.70%
Allowance for loan losses	$ 0			$ 0
Provision for impairment	1,440,000	$ 1,849,000
Deposits	109,113,000	1,842,000		4,236,000
Deposits in excess of amount insured by FDIC	108,900,000			4,000,000
Contingent rent	300,000	500,000
Capitalized offering costs	$ 46,000,000			35,100,000
Percentage of taxable income require to REIT	90.00%
Provision for income tax	$ 0
Uncertain tax positions, interest or penalties	0	0
Uncertain tax position, interest or penalties accrued	0			$ 0
Mortgage loan receivable	$ 9,312,000	$ 14,854,000
Number of loan receivable agreements secured | Loan	3	0		4
Number of reportable segments | Segment	1
Common stock, conversion basis	one-for-one basis
Right-of-use asset	$ 3,700,000
Lease liability	$ 4,617,000
ASU 2016-02
Summary Of Significant Accounting Policies [Line Items]
Right-of-use asset			$ 4,800,000
Lease liability			$ 4,800,000
Variable Interest Entities ("VIEs") | Mortgage Loan Receivable
Summary Of Significant Accounting Policies [Line Items]
Mortgage loan receivable				$ 5,700,000
Mortgage loan receivable, maximum loss exposure				5,700,000
Liabilities associated with investment				0
Number of loan receivable agreements secured | Loan	0
Federal
Summary Of Significant Accounting Policies [Line Items]
Open tax year	2016 2017 2018
State
Summary Of Significant Accounting Policies [Line Items]
Open tax year	2016 2017 2018
Base Rent
Summary Of Significant Accounting Policies [Line Items]
Allowance for doubtful accounts receivable	$ 200,000			200,000
Straight-line Rent
Summary Of Significant Accounting Policies [Line Items]
Allowance for doubtful accounts receivable	0			$ 0
Maximum
Summary Of Significant Accounting Policies [Line Items]
Adjustment to rental revenue	100,000
Real Estate Investments
Summary Of Significant Accounting Policies [Line Items]
Depreciation	$ 7,700,000	$ 5,200,000
Buildings | Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life	40 years
Site Improvements
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life	15 years