Summary of Significant Accounting Policies - Reconciliation of GAAP Net Income to Taxable Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Net income (loss)	$ 6,659	$ 5,389	$ 5,497
Book depreciation and amortization	66,260	54,782	45,797
Above/Below market lease amortization	(8,593)	(8,517)	(7,153)
Straight-line rent and other non-cash adjustments	(5,619)	(2,776)	(108)
Book/Tax differences on unearned rent	301	16	(37)
Book/Tax differences on stock based compensation	3,039	2,663	2,780
Book/Tax differences on development profit on lump sum payments	3,413
Book/Tax differences on post IPO property acquisition costs			620
Book/Tax differences on fee waiver income from seller	1,400
Other book/tax differences, net	749	383	901
Tax depreciation	(34,612)	(25,552)	(20,622)
Loss attributable to non-controlling interest	(6,021)	(5,180)	(8,474)
Taxable income subject to distribution requirements	$ 26,976	$ 21,208	$ 19,201