Acquisitions and Dispositions - Unaudited Pro Forma Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Acquisition [Line Items]
Revenue	$ 95,623	$ 89,349	$ 283,152	$ 230,026
Net income	13,174	15,799	37,179	28,509
Net income available to common shareholders	$ 12,635	$ 14,772	$ 35,251	$ 25,743
Earnings per share - basic (in dollars per share)	$ 0.07	$ 0.08	$ 0.22	$ 0.16
Earnings per share - diluted (in dollars per share)	$ 0.07	$ 0.08	$ 0.22	$ 0.16
Weighted average number of shares outstanding - basic	177,847,424	177,847,424	157,542,167	157,542,167
Weighted average number of shares outstanding - diluted (in shares)	183,298,145	183,298,145	162,480,918	162,480,918
Operating Partnership
Business Acquisition [Line Items]
Revenue	$ 95,623	$ 89,349	$ 283,152	$ 230,026
Net income	13,174	15,799	37,179	28,509
Net income available to common shareholders	$ 13,015	$ 15,187	$ 36,295	$ 26,535
Earnings per unit - basic (in dollars per unit)	$ 0.07	$ 0.08	$ 0.22	$ 0.16
Earnings per unit - diluted (in dollars per unit)	$ 0.07	$ 0.08	$ 0.22	$ 0.16
Weighted average limited partnership units outstanding, basic (in shares)	183,227,405	183,227,405	162,205,324	162,205,324
Denominator for earnings per unit - diluted (in shares)	183,298,145	183,298,145	162,480,918	162,480,918