Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	Mar. 31, 2017	Mar. 31, 2018	Dec. 31, 2017	Apr. 12, 2017
Class of Stock [Line Items]
Common stock shares authorized (in shares)		140,000,000	140,000,000	140,000,000
Common stock par value (in dollars per share)		$ 0.01	$ 0.01	$ 0.01
Preferred stock shares authorized (in shares)		10,000,000	10,000,000	10,000,000
Preferred stock par value (in dollars per share)		$ 0.01	$ 0.01	$ 0.01
Common stock shares issued (in shares)		53,284,470	53,284,470
Common stock shares outstanding (in shares)		53,284,470	53,284,470
Cash distributions paid	$ 190.0
Assets held in trust		$ 4.6
Restricted Stock
Class of Stock [Line Items]
Common stock par value (in dollars per share)		$ 0.01