Earnings Per Share and Earnings Per Unit - Schedule of Earnings Per Share and Earnings Per Unit (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
Earnings Per Share
Units excluded from the computation of diluted earnings per share (in shares)		405,343
Numerator for earnings per share - basic:
Net income		$ 12,539	$ 10,294	$ 29,586	$ 22,902
Operating Partnership		(362)	(255)	(823)	(629)
Partially owned properties	[1]	(53)	(176)	(379)	(553)
Preferred distributions		(106)	(436)	(505)	(1,421)
Numerator for earnings per share - basic		12,018	9,427	27,879	20,299
Numerator for earnings per share - diluted:
Numerator for earnings per share - basic		12,018	9,427	27,879	20,299
Operating Partnership net income		362	255	823	629
Numerator for earnings per share - diluted		$ 12,380	$ 9,682	$ 28,702	$ 20,928
Denominator for earnings per share - basic and diluted:
Weighted average number of shares outstanding - basic (in shares)		177,847,424	134,608,396	157,542,167	122,973,862
Effect of dilutive securities:
Noncontrolling interest - Operating Partnership units (in shares)		5,379,981	3,618,988	4,663,157	3,778,014
Weighted average number of shares outstanding - diluted (in shares)		183,298,145	138,880,787	162,480,918	127,395,989
Earnings per share - basic (in dollars per share)		$ 0.07	$ 0.07	$ 0.18	$ 0.17
Earnings per share - diluted (in dollars per share)		$ 0.07	$ 0.07	$ 0.18	$ 0.16
Restricted common shares
Effect of dilutive securities:
Effect of dilutive securities, restricted shares and RSUs (in shares)		70,740	208,892	85,689	203,020
Restricted share units (RSUs)
Effect of dilutive securities:
Effect of dilutive securities, restricted shares and RSUs (in shares)		0	444,511	189,905	441,093
Operating Partnership
Numerator for earnings per share - basic:
Net income		$ 12,539	$ 10,294	$ 29,586	$ 22,902
Partially owned properties	[2]	(53)	(176)	(379)	(553)
Preferred distributions		(106)	(436)	(505)	(1,421)
Numerator for earnings per share - basic		12,380	9,682	28,702	20,928
Numerator for earnings per unit - basic and diluted		$ 12,380	$ 9,682	$ 28,702	$ 20,928
Weighted average limited partnership units outstanding, basic (in shares)		183,227,405	138,227,384	162,205,324	126,751,876
Numerator for earnings per share - diluted:
Numerator for earnings per share - basic		$ 12,380	$ 9,682	$ 28,702	$ 20,928
Effect of dilutive securities:
Denominator for earnings per unit - diluted (in shares)		183,298,145	138,880,787	162,480,918	127,395,989
Earnings per unit - basic (dollars per share)		$ 0.07	$ 0.07	$ 0.18	$ 0.17
Earnings per unit - diluted (dollars per share)		$ 0.07	$ 0.07	$ 0.18	$ 0.16
Operating Partnership | Restricted common shares
Effect of dilutive securities:
Effect of dilutive securities, restricted shares and RSUs (in shares)		70,740	208,892	85,689	203,020
Operating Partnership | Restricted share units (RSUs)
Effect of dilutive securities:
Effect of dilutive securities, restricted shares and RSUs (in shares)		0	444,511	189,905	441,093

[1] Includes amounts attributable to redeemable noncontrolling interests. No such adjustments are required for the three and nine months ended September 30, 2016.

[2] Includes amounts attributable to redeemable noncontrolling interests. No such adjustments are required for the three and nine months ended September 30, 2016.