Consolidated Statements of Income - USD ($)		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Rental revenues		$ 313,006,000	$ 259,673,000	$ 186,301,000
Expense recoveries		97,989,000	75,425,000	45,875,000
Interest income on real estate loans and other		11,556,000	8,486,000	8,858,000
Revenues		422,551,000	343,584,000	241,034,000
Expenses:
Interest expense		66,183,000	47,008,000	23,864,000
General and administrative		28,816,000	22,957,000	18,397,000
Operating expenses		122,620,000	97,035,000	65,999,000
Depreciation and amortization		158,389,000	125,159,000	86,589,000
Acquisition expenses		0	16,744,000	14,778,000
Impairment loss		0	965,000	0
Total expenses		376,008,000	309,868,000	209,627,000
Income before equity in income of unconsolidated entities and gain on sale of investment properties, net:		46,543,000	33,716,000	31,407,000
Equity in income of unconsolidated entities		114,000	183,000	115,000
Gain on sale of investment properties, net		11,664,000	5,874,000	0
Net income		58,321,000	39,773,000	31,522,000
Net income attributable to noncontrolling interests:
Operating Partnership		(1,576,000)	(1,136,000)	(825,000)
Partially owned properties	[1]	(515,000)	(491,000)	(716,000)
Net income attributable to controlling interest		56,230,000	38,146,000	29,981,000
Preferred distributions		(1,340,000)	(731,000)	(1,857,000)
Net income attributable to common shareholders		$ 54,890,000	$ 37,415,000	$ 28,124,000
Net income per share:
Basic (in dollars per share)		$ 0.30	$ 0.23	$ 0.22
Diluted (in dollars per share)		$ 0.30	$ 0.23	$ 0.22
Weighted average common shares:
Basic (in shares)		182,064,064	163,123,109	126,143,114
Diluted (in shares)		187,526,762	168,231,299	130,466,893
Dividends and distributions declared per common share and OP unit (in dollars per share)		$ 0.920	$ 0.915	$ 0.900
Operating Partnership
Revenues:
Rental revenues		$ 313,006,000	$ 259,673,000	$ 186,301,000
Expense recoveries		97,989,000	75,425,000	45,875,000
Interest income on real estate loans and other		11,556,000	8,486,000	8,858,000
Revenues		422,551,000	343,584,000	241,034,000
Expenses:
Interest expense		66,183,000	47,008,000	23,864,000
General and administrative		28,816,000	22,957,000	18,397,000
Operating expenses		122,620,000	97,035,000	65,999,000
Depreciation and amortization		158,389,000	125,159,000	86,589,000
Acquisition expenses		0	16,744,000	14,778,000
Impairment loss		0	965,000	0
Total expenses		376,008,000	309,868,000	209,627,000
Income before equity in income of unconsolidated entities and gain on sale of investment properties, net:		46,543,000	33,716,000	31,407,000
Equity in income of unconsolidated entities		114,000	183,000	115,000
Gain on sale of investment properties, net		11,664,000	5,874,000	0
Net income		58,321,000	39,773,000	31,522,000
Net income attributable to noncontrolling interests:
Partially owned properties	[1]	(515,000)	(491,000)	(716,000)
Net income attributable to controlling interest		57,806,000	39,282,000	30,806,000
Preferred distributions		(1,340,000)	(731,000)	(1,857,000)
Net income attributable to common shareholders		$ 56,466,000	$ 38,551,000	$ 28,949,000
Earnings per unit:
Earnings per unit - basic (in dollars per share)		$ 0.30	$ 0.23	$ 0.22
Earnings per unit - diluted (in dollars per share)		$ 0.30	$ 0.23	$ 0.22
Weighted average common units - basic (in shares)		187,393,334	167,963,076	129,835,209
Weighted average common units - diluted (in shares)		187,526,762	168,231,299	130,466,893
Distributions declared per common OP Unit (in dollars per share)		$ 0.920	$ 0.915	$ 0.900

[1] Includes amounts attributable to redeemable noncontrolling interest.