SCHEDULE IV (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Length of Time After Project Completion When Development Cost Ceased Being Capitalized		1 year
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Principal Amount of Delinquent Loans	[1]	$ 0
Number of Loans	[2]	1
Non-recourse first mortgage loan Face Amount, Total mortgage		$ 1,679
Changes in the mortgage loans [Roll Forward]
Balance at end of year	[3]	1,679
Income Tax Basis of Mortgage Loans on Real Estate		$ 1,680
Development properties [Member]
Changes in the mortgage loans [Roll Forward]
Length of Time After Project Acquisition (for Value-add) or Shell Completion (for Developments) When Project Transfers to Real Estate Properties		1 year
Value-add properties [Member]
Changes in the mortgage loans [Roll Forward]
Length of Time After Project Acquisition (for Value-add) or Shell Completion (for Developments) When Project Transfers to Real Estate Properties		1 year
First Mortgage [Member]
Changes in the mortgage loans [Roll Forward]
Balance at beginning of year	[4]	$ 2,594	$ 4,581	$ 4,752
Payments on mortgage loans receivable	[4]	(915)	(1,987)	(171)
Balance at end of year	[4]	1,679	$ 2,594	$ 4,581
JCB Limited - California - B [Member] | First Mortgage [Member] | Buildings [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Principal Amount of Delinquent Loans	[1]	$ 0
Number of Loans		1
Stated interest rate (in hundredths)		5.15%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date		2022-12
Periodic Payment Terms		Principal and interest due monthly
Non-recourse first mortgage loan Face Amount, Total mortgage		$ 1,679
Changes in the mortgage loans [Roll Forward]
Balance at end of year	[3]	$ 1,679

[1] Interest in arrears for three months or less is disregarded in computing principal amount of loans subject to delinquent interest.

[2] Reference is made to allowance for possible losses on mortgage loans receivable in the Notes to Consolidated Financial Statements.

[3] The aggregate cost for federal income tax purposes is approximately $1.68 million.  The federal income tax return for the year ended December 31, 2019, has not been filed and, accordingly, the income tax basis of mortgage loans as of December 31, 2019, is based on preliminary data.

[4] Changes in mortgage loans follow:   Years Ended December 31, 2019   2018   2017 (In thousands) Balance at beginning of year $ 2,594
  4,581
  4,752
Payments on mortgage loans receivable (915 )   (1,987 )   (171 ) Balance at end of year $ 1,679
  2,594
  4,581