Organization and Business - (Details) - USD ($)	Aug. 05, 2016	Feb. 22, 2019	Dec. 31, 2018	Dec. 31, 2017
Organization and Business
Common stock, shares authorized (in shares)			500,000,000	500,000,000
Common stock, par value (in dollars per share)			$ 0.01	$ 0.01
Subsequent Events
Organization and Business
Amount remaining available		$ 163,700,000
2016 ATM Program | ATM Program | Maximum
Organization and Business
Aggregate offering price of common stock	$ 300,000,000.0