Equity - Change in Net Income Attributable to Common Shareholders (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Class of Stock [Line Items]
Net income attributable to common stockholders	$ 18,806	$ 15,973	$ 45,375	$ 34,490
Increase in additional paid-in capital for the conversion of OP Units into common stock			0
Change from net income attributable to common stockholders and transfers from non-controlling interests	20,759	20,989	56,462	54,707
Additional Paid-In Capital
Class of Stock [Line Items]
Increase in additional paid-in capital for the conversion of OP Units into common stock	$ 1,953	$ 5,016	$ 11,087	$ 20,217