Equity - Net Income Attributable to Common Stockholders and Transfers (to) from Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Stockholders' Equity Note [Abstract]
Net income attributable to common stockholders	$ 25,614	$ 31,848	$ 64,907	$ 65,696
Exchange of OP Units with noncontrolling interests			13,261	17,733
Repurchase of OP Units from noncontrolling interests			0	(498)
Net transfers from noncontrolling interests			13,261	17,235
Change from net income attributable to common stockholders and transfers from noncontrolling interests			$ 78,168	$ 82,931