Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Cash Flows from Operating Activities:
Net income / (loss)	$ 23,475	$ 6,985	$ (72)
Adjustments to reconcile net income/ (loss) to net cash provided by operating activities
Depreciation	8,599	2,629	915
Stock-based compensation	2,495	1,465	1,719
Amortization of discounts on short-term investments	(3,738)	(955)	0
Amortization of debt discounts and issuance costs	1,678		0
Changes in assets and liabilities
Other assets, net	(619)	(173)	(155)
Accounts payable and accrued expenses	1,427	886	992
Rent received in advance and tenant security deposits	11,617	4,856	1,616
Net cash provided by operating activities	44,934	15,693	5,015
Cash Flows from Investing Activities:
Purchases of investments in real estate	(259,889)	(57,474)	(32,734)
Reimbursements of tenant improvements and construction funding	(84,677)	(22,293)	(5,911)
Deposits in escrow for acquisitions	(650)		0
Purchases of short-term investments	(255,664)	(184,988)	0
Maturities of short-term investments	260,250	65,500	0
Net cash used in investing activities	(340,630)	(199,255)	(38,645)
Cash Flows from Financing Activities:
Issuance of common stock, net of offering costs	286,292	193,223	0
Payment of Class A common stock offering costs	0		276
Issuance of Series A Preferred Stock, net of offering costs	0		14,009
Net proceeds from issuance of exchangeable senior notes	138,545		0
Dividends paid to common stockholders	(22,584)	(6,642)	(1,050)
Dividends paid to preferred stockholders	(1,352)	(1,337)	0
Taxes paid related to net share settlement of equity awards	(939)	(390)	(298)
Net cash provided by financing activities	399,962	184,854	12,385
Net increase in cash, cash equivalents and restricted cash	(104,266)	(1,292)	21,245
Cash, cash equivalents and restricted cash, beginning of period	13,050	11,758	33,003
Cash, cash equivalents and restricted cash, end of period	117,316	13,050	11,758
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	3,055		0
Supplemental disclosure of non-cash investing and financing activities:
Accrual for reimbursements of tenant improvements and construction funding	24,968	2,433	20
Accrual for common and preferred stock dividends declared	12,975	$ 3,759	1,198
Accrual for stock issuance costs	22		41
Operating lease liability for obtaining right of use asset	$ 1,211		$ 0