Equity - Changes in Ownership Interest in Operating Partnership (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stockholders' Equity Note [Abstract]
Net income attributable to common stockholders	$ 28,701	$ 28,206
Transfers from noncontrolling interests:
Exchange of OP Units with noncontrolling interests	363	5,199
Repurchase of OP Units from noncontrolling interests	(291)	0
Net transfers from noncontrolling interests	72	5,199
Change from net income attributable to common stockholders and transfers from noncontrolling interests	$ 28,773	$ 33,405