Noncontrolling Interest Represented by Preferred Operating Partnership Units - Summary of Noncontrolling Interests by Operating Partnership Preferred Units (Details) - Operating Partnership	Jun. 30, 2018 shares
Series A Participating Redeemable Preferred Units | Series A Units
Noncontrolling Interest [Line Items]
Preferred units outstanding (in shares)	875,480
Series B Redeemable Preferred Units | Series B Units
Noncontrolling Interest [Line Items]
Preferred units outstanding (in shares)	1,676,087
Series C Convertible Redeemable Preferred Units | Series C Units
Noncontrolling Interest [Line Items]
Preferred units outstanding (in shares)	704,016
Series D Convertible Redeemable Preferred Units | Series D Units
Noncontrolling Interest [Line Items]
Preferred units outstanding (in shares)	3,682,521