Significant Accounting Policies - Additional Information (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016 acquisition	Dec. 31, 2018 USD ($) business_segment shares	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares	Jan. 01, 2019 USD ($)	Oct. 01, 2016 USD ($)	Jan. 01, 2016 USD ($)
Accounting Policies [Line Items]
Business segments | business_segment		4
Interest receivable		$ 271	$ 7,071	$ 3,222
Common shares tendered for tax withholding		409	289	218
Straight-line rent adjustments		2,700	1,200	1,100
Contingent rents included in revenue		300	400	400
Leasing incentive amortization		700	800	800
Interest capitalized		5,000	1,300	1,000
Indirect project costs		3,100	2,400	1,700
Capitalized preacquisition development costs		1,214	1,352
Impairment charges		1,500
Accounts receivable, net		19,016	15,691
Allowance for doubtful accounts		600	500
Stock-based compensation expense		1,281	1,323	1,082
Capitalized stock-based compensation		$ 700	$ 400	$ 300
Percentage of taxable income for distributions to stockholders		90.00%
Dilutive shares outstanding (in shares) | shares		0	0	0
Number of acquisitions | acquisition	2
Accrued Straight-line Rental Revenue
Accounting Policies [Line Items]
Accounts receivable, net		$ 15,200	$ 12,800
Accounting Standards Update 2017-01
Accounting Policies [Line Items]
Cost capitalized subsequent to acquisition						$ 700
Pro Forma | Accounting Standards Update 2017-01
Accounting Policies [Line Items]
Cost capitalized subsequent to acquisition							$ 1,400
Reclassification Of Earned Interest Income | Restatement Adjustment
Accounting Policies [Line Items]
Interest receivable			7,100	$ 3,200
Reclassification For Shares Tendered For Tax Withholding | Restatement Adjustment
Accounting Policies [Line Items]
Common shares tendered for tax withholding			$ 300	$ 200
Minimum | Forecast | Accounting Standards Update 2016-02
Accounting Policies [Line Items]
Right-of-use assets					$ 30,000
Operating lease liability					30,000
Maximum | Forecast | Accounting Standards Update 2016-02
Accounting Policies [Line Items]
Right-of-use assets					45,000
Operating lease liability					$ 45,000