Acquisitions and Dispositions - Unaudited Pro Forma Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Business Acquisition [Line Items]
Revenue	$ 87,755	$ 69,579	$ 179,092	$ 130,423
Net income	11,251	7,933	19,409	12,286
Net income available to common shareholders	$ 10,559	$ 7,210	$ 18,146	$ 10,560
Earnings per share - basic (in dollars per share)	$ 0.07	$ 0.05	$ 0.12	$ 0.07
Earnings per share - diluted (in dollars per share)	$ 0.07	$ 0.05	$ 0.12	$ 0.07
Weighted Average Basic Shares Outstanding, Pro Forma	155,366,080	155,366,080	147,221,602	147,221,602
Weighted average number of shares outstanding - diluted (in shares)	161,012,360	161,012,360	151,912,432	151,912,432
Operating Partnership
Business Acquisition [Line Items]
Revenue	$ 87,755	$ 69,579	$ 179,092	$ 130,423
Net income	11,251	7,933	19,409	12,286
Net income available to common shareholders	$ 10,904	$ 7,436	$ 18,684	$ 10,924
Earnings per unit - basic (in dollars per unit)	$ 0.07	$ 0.05	$ 0.12	$ 0.07
Earnings per unit - diluted (in dollars per unit)	$ 0.07	$ 0.05	$ 0.12	$ 0.07
Weighted average limited partnership units outstanding, basic (in shares)	160,765,345	160,765,345	151,520,407	151,520,407
Denominator for earnings per unit - diluted (in shares)	161,012,360	161,012,360	151,912,432	151,912,432