Organization and Summary of Significant Accounting Policies - Significant Non-Cash Transactions (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
	Sep. 26, 2019	Sep. 30, 2019	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Non-cash lease termination income			$ 4,200		$ 4,200
Line of credit facilities gross repayments				$ 39,000	53,000	$ 403,000
Line of credit facilities gross borrowings				229,000	65,000	309,000
Increase (decrease) in accrued construction costs				$ (8,500)	15,700	(8,300)
2014 5-Year Term Loan and 2015 5-Year Term Loan
Summary Of Significant Accounting Policies [Line Items]
Line of credit facilities gross repayments					$ 150,000
2014 7-Year Term Loan
Summary Of Significant Accounting Policies [Line Items]
Line of credit facilities gross repayments						$ 150,000
Wyoming Valley Mall | Commercial Real Estate | Mortgage Loan
Summary Of Significant Accounting Policies [Line Items]
Debt default, amount	$ 72,800
Repayments of cash and escrow balance	$ 7,500	$ 7,500