Real Estate Joint Ventures - Narrative (Details) - Variable Interest Entities - apartment	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Apr. 30, 2017
Pier Park Crossings JV
Variable Interest Entity [Line Items]
Number of apartments to be designed, developed and constructed				240
Variable interest entity, qualitative or quantitative information, ownership percentage	75.00%		75.00%
WindMark JV
Variable Interest Entity [Line Items]
Variable interest entity, qualitative or quantitative information, ownership percentage	49.00%		49.00%
Pier Park North
Variable Interest Entity [Line Items]
Variable interest entity, qualitative or quantitative information, ownership percentage	60.00%		60.00%
Artisan Park, L.L.C
Variable Interest Entity [Line Items]
Variable interest entity, qualitative or quantitative information, ownership percentage		100.00%	74.00%