Financial Instruments and Fair Value Measurements - Liabilities measured at FV (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Jan. 31, 2019
Interest rate swap
Financial instruments and fair value measurements
Notional amount			$ 20,000
Level 2 | Interest rate swap | Other liabilities.
Financial instruments and fair value measurements
Derivative liabilities	$ 1,200	$ 300
Recurring basis
Financial instruments and fair value measurements
Liabilities	2,044	336
Recurring basis | Interest rate swap | Other liabilities.
Financial instruments and fair value measurements
Derivative liabilities	1,201	336
Recurring basis | Interest rate swap | Investment in unconsolidated joint ventures
Financial instruments and fair value measurements
Derivative liabilities	843
Recurring basis | Level 2
Financial instruments and fair value measurements
Liabilities	2,044	336
Recurring basis | Level 2 | Interest rate swap | Pier Park TPS JV
Financial instruments and fair value measurements
Derivative liabilities	800
Recurring basis | Level 2 | Interest rate swap | Other liabilities.
Financial instruments and fair value measurements
Derivative liabilities	1,201	$ 336
Recurring basis | Level 2 | Interest rate swap | Investment in unconsolidated joint ventures
Financial instruments and fair value measurements
Derivative liabilities	$ 843
Pier Park TPS JV
Financial instruments and fair value measurements
Notional amount				$ 14,400