Joint Ventures - Summarized financial information by unconsolidated JV (Details) $ in Thousands				3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020 USD ($) item home	Jul. 05, 2019 USD ($)	Jan. 14, 2019 USD ($)	Sep. 30, 2020 USD ($) item home	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) item home	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jan. 31, 2020 USD ($)	Nov. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Jan. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Apr. 30, 2018 item
Investments
Outstanding debt	$ 145,759			$ 145,759		$ 145,759		$ 94,507
Summarized financial information
Property and equipment, net	18,750			18,750		18,750		19,018
Investment in real estate	530,673			530,673		530,673		430,776
Cash and cash equivalents	102,351			102,351	$ 165,311	102,351	$ 165,311	185,716
Other assets	58,471			58,471		58,471		52,069
Total assets	1,003,913			1,003,913		1,003,913		909,233
Debt, net	143,375			143,375		143,375		92,529
Other liabilities	70,774			70,774		70,774		57,200
Equity	552,420			552,420	522,550	552,420	522,550	529,670	$ 542,650			$ 542,140		$ 533,111
Total liabilities and equity	1,003,913			1,003,913		1,003,913		$ 909,233
Total revenue				42,041	32,856	96,695	84,426
Other operating expenses				5,113	5,054	16,975	16,116
Depreciation and amortization				3,303	2,629	9,394	7,162
Total expenses				31,016	25,436	75,890	68,297
Operating income				11,025	7,420	20,805	16,129
Interest expense				(3,379)	(3,109)	(10,113)	(9,075)
Net income				7,782	$ 5,826	25,666	18,034
Sea Sound Apartments JV, Partner
Investments
Cash contributed						6,900
Latitude Margaritaville Watersound JV
Investments
Value of land contributed						35,000
Cash contributed						4,300
Net present value of land contribution	16,600			16,600		$ 16,600
Imputed interest rate (as a percent)						5.75%
Amount of infrastructure improvements completed	700			700		$ 700
Variable interest entity, ownership percentage						50.00%		50.00%
Average amount of land contribution returned per home						$ 10
Summarized financial information
Historical cost basis of land contributed	$ 1,300			$ 1,300		1,300
Sea Sound Apartments JV
Investments
Value of land contributed						5,100
Mitigation bank credits contributed						400
Cash contributed						$ 4,900
Ownership percentage	60.00%			60.00%		60.00%
Summarized financial information
Net income				$ 0		$ 0
Pier Park TPS JV
Investments
Value of land contributed			$ 1,700
Mitigation bank credits contributed							100
Cash contributed							$ 200
Ownership percentage	50.00%			50.00%		50.00%		50.00%
Busy Bee JV (SJBB, LLC)
Investments
Value of land contributed		$ 1,400
Investment in unconsolidated joint venture	$ 1,200			$ 1,200		$ 1,200		$ 1,200
Ownership percentage	50.00%			50.00%		50.00%		50.00%
Unconsolidated joint ventures
Investments
Outstanding debt	$ 23,828			$ 23,828		$ 23,828		$ 8,242
Latitude Margaritaville Watersound JV
Investments
Number of homesites under development | item	248			248		248
Number of homesites fully permitted and anticipated to commence development | item	381			381		381
Period within which units fully permitted are expected to commence development	30 days
Number of homesites units under development or fully permitted and anticipated to commence development | item	629			629		629
Number of units to be developed and constructed | home	3,500			3,500		3,500
Amount of infrastructure improvements completed	$ 700			$ 700		$ 700
Outstanding debt	1,542			1,542		1,542
Summarized financial information
Investment in real estate	10,328			10,328		10,328		1,116
Cash and cash equivalents	1,225			1,225		1,225		525
Other assets	162			162		162
Total assets	11,715			11,715		11,715		1,641
Debt, net	1,542			1,542		1,542
Other liabilities	551			551		551		58
Equity	9,622			9,622		9,622		1,583
Total liabilities and equity	$ 11,715			11,715		11,715		1,641
Total expenses				260		595
Net income				$ (260)		$ (595)
Sea Sound Apartments JV
Investments
Number of units to be developed and constructed | item	300			300		300
Outstanding debt	$ 1,260			$ 1,260		$ 1,260
Summarized financial information
Investment in real estate	20,729			20,729		20,729
Total assets	20,729			20,729		20,729
Debt, net	800			800		800
Other liabilities	2,646			2,646		2,646
Equity	17,283			17,283		17,283
Total liabilities and equity	20,729			20,729		20,729
Sea Sound Apartments JV | Sea Sound Apartments JV Loan
Investments
Loan amount										$ 40,300
Outstanding debt	1,300			1,300		1,300
Pier Park TPS JV
Investments
Number of units to be developed and constructed | item															124
Outstanding debt	14,388			14,388		14,388		6,791
Summarized financial information
Property and equipment, net	18,320			18,320		18,320		14,775
Cash and cash equivalents	1,496			1,496		1,496		51
Other assets	531			531		531		12
Total assets	20,347			20,347		20,347		14,838
Debt, net	14,087			14,087		14,087		6,480
Other liabilities	1,876			1,876		1,876		2,193
Equity	4,384			4,384		4,384		6,165
Total liabilities and equity	20,347			20,347		20,347		14,838
Total revenue				1,001		1,534
Cost of revenue				515		789
Other operating expenses				92		130
Depreciation and amortization				379		578
Total expenses				986		1,497
Operating income				15		37
Interest expense				(98)		(132)
Net income				(83)		(95)
Pier Park TPS JV | Pier Park TPS JV Loan
Investments
Loan amount													$ 14,400
Outstanding debt	14,400			14,400		14,400		6,800
Busy Bee JV (SJBB, LLC)
Investments
Amount of note receivable from JV partner	200			200		200
Outstanding debt	6,638			6,638		6,638		1,451
Summarized financial information
Property and equipment, net	8,670			8,670		8,670		3,886
Cash and cash equivalents	202			202		202		36
Other assets	760			760		760		28
Total assets	9,632			9,632		9,632		3,950
Debt, net	6,548			6,548		6,548		1,349
Other liabilities	582			582		582		181
Equity	2,502			2,502		2,502		2,420
Total liabilities and equity	9,632			9,632		9,632		3,950
Total revenue				3,360		3,360
Cost of revenue				2,510		2,510
Other operating expenses				530		580
Depreciation and amortization				135		135
Total expenses				3,175		3,225
Operating income				185		135
Interest expense				(39)		(54)
Net income				146		81
Busy Bee JV (SJBB, LLC) | Busy Bee JV Construction Loan, due November 2035
Investments
Loan amount											$ 5,400
Outstanding debt	5,400			5,400		5,400		1,400
Busy Bee JV (SJBB, LLC) | Busy Bee JV Equipment Loan, due November 2027
Investments
Loan amount											$ 1,200
Outstanding debt	$ 1,200			$ 1,200		$ 1,200		$ 100