Financing Activity - Credit Agreements (Details)						3 Months Ended		9 Months Ended
	Oct. 01, 2021	Jun. 30, 2021	Feb. 08, 2021 USD ($)	Dec. 10, 2020 USD ($) Agreement	Oct. 16, 2020 USD ($)	Sep. 30, 2021	Mar. 31, 2021 USD ($) ft² Property Award	Sep. 30, 2020	Dec. 31, 2020 USD ($)	Nov. 01, 2020 USD ($)
Debt Instrument [Line Items]
Outstanding line of credit							$ 54,830,000		$ 54,830,000
Amounts equal to greater than termination or modification of lease							2,500,000
Maximum
Debt Instrument [Line Items]
Amounts received on behalf of guarantor in consideration of termination or modification of lease.							$ 3,500,000
Minimum
Debt Instrument [Line Items]
Leased premises | ft²							7,500
Debt instrument discounted amount							$ 750,000
Percentage of aggregate contractual base rent							25.00%
Outstanding obligations							$ 3,500,000
Unsecured Debt
Debt Instrument [Line Items]
Debt issuance costs, line of credit arrangements							$ 11,900,000
First Lien Credit Agreement Base Rate Loans | Federal Funds Rate
Debt Instrument [Line Items]
Debt, variable interest rate							0.50%
First Lien Credit Agreement Base Rate Loans | LIBOR Market Index Rate
Debt Instrument [Line Items]
Debt, variable interest rate							1.00%
First Lien Credit Agreement Base Rate Loans | Base Rate
Debt Instrument [Line Items]
Debt, variable interest rate							1.50%
Second Lien Credit Agreement Base Rate Loans | Federal Funds Rate
Debt Instrument [Line Items]
Debt, variable interest rate							0.50%
Second Lien Credit Agreement Base Rate Loans | LIBOR Market Index Rate
Debt Instrument [Line Items]
Debt, variable interest rate							1.00%
Second Lien Credit Agreement Base Rate Loans | Base Rate
Debt Instrument [Line Items]
Debt, variable interest rate							1.50%
Debt instrument interest rate							7.00%
Second Lien Credit Agreement LIBOR Loans | Maximum
Debt Instrument [Line Items]
Debt, variable interest rate							0.50%
Second Lien Credit Agreement LIBOR Loans | LIBOR
Debt Instrument [Line Items]
Debt, variable interest rate							8.00%
Credit Agreements
Debt Instrument [Line Items]
Number of credit agreements				2			3
Debt instrument maturity period							2022-12	2022-12
Debt instrument, payment terms							2 years
Number of properties | Property							12
Number of malls | Property							9
Number of additional parcels | Property							3
Debt instrument extension term							1 year
Debt instrument extended maturity period							2023-12
Debt instrument minimum liquidity							$ 35,000,000.0
Percentage of minimum corporate debt yield							8.00%
Percentage of maximum loan to value ratio							105.00%
Debt Instrument, restrictive covenants							The Credit Agreements each provide for a two-year maturity of December 2022 (the “Maturity Date”), subject to a one-year extension to December 2023 at the borrowers’ option, subject to (i) minimum liquidity of $35.0 million, (ii) a minimum corporate debt yield of 8.0%, (iii) a maximum loan-to-value ratio of 105% for the total first lien and second lien loans and letters of credit and the Borrowing Base Properties as determined by an appraisal and (iv) no default or event of default existing and our representations and warranties being true in all material respects. The loans under the Credit Agreements are repayable in full on the Maturity Date, subject to mandatory prepayment provisions in the event of certain events including asset sales, incurrence of indebtedness, issuances of equity and receipt of casualty insurance proceeds. The terms of our Credit Agreements place restrictions on, among other things, and subject to certain exceptions, our ability to make certain restricted payments (including payments of dividends), make certain types of investments and acquisitions, issue redeemable securities, incur additional indebtedness, incur liens on our assets, enter into agreements with a negative pledge, make certain intercompany transfers, merge, consolidate, or sell our assets or the equity interests in our subsidiaries, amend our organizational documents or material contracts, enter into certain transactions with affiliates, or enter into derivatives contracts. Additionally, if we receive net cash proceeds from certain capital events (including equity issuances), we are required to prepay loans under our Credit Agreements. In addition, the Credit Agreements contain cross-default provisions that trigger an event of default if we fail to make certain payments or otherwise fail to comply with our obligations with respect to certain of our other indebtedness.
Minimum liquidity comprised of unrestricted cash held in certain deposit accounts subject to control agreements							$ 25,000,000.0
Maximum certain other deposit account not subject to control agreement							5,000,000.0
Maximum cash not retain in property level accounts held by subsidiaries							$ 6,500,000
Credit Agreements | Forecast
Debt Instrument [Line Items]
Percentage of minimum corporate debt yield	7.25%					6.50%
Percentage of minimum senior debt yield		11.35%
Credit Agreements | Term Loans
Debt Instrument [Line Items]
Debt instrument, payment terms							7 years
Outstanding borrowings							$ 933,600,000			$ 590,000,000.0
Credit Agreements | First Lien Revolving Facility
Debt Instrument [Line Items]
Outstanding line of credit							54,800,000
Remaining borrowing capacity							75,200,000
Credit Agreements | 2018 Revolving Facility
Debt Instrument [Line Items]
Maximum borrowing							$ 375,000,000.0
Debt instrument, payment terms							7 years
Outstanding line of credit										375,000,000.0
Credit Agreements | A2018 Term Loan Facility
Debt Instrument [Line Items]
Maximum borrowing							$ 300,000,000.0
Credit Agreements | A2014 Seven Year Term Loan
Debt Instrument [Line Items]
Maximum borrowing							250,000,000.0
Credit Agreements | Bridge Facility
Debt Instrument [Line Items]
Maximum borrowing							$ 30,000,000.0
Outstanding line of credit										$ 55,000,000.0
Debt instrument, maturity date							Oct. 31, 2020
Ability request additional commitment amount							$ 25,000,000.0
Increase in aggregate amount of commitments					$ 25,000,000.0
Secured First Lien Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing				$ 130,000,000.0
Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing				10,000,000.0
First Lien Term Loan Facility
Debt Instrument [Line Items]
Maximum borrowing				384,500,000
Second Lien Term Loan Facility
Debt Instrument [Line Items]
Maximum borrowing				$ 535,200,000
7-Year Term Loan
Debt Instrument [Line Items]
Loan agreement entered date				Jan. 08, 2014
Debt instrument, payment terms				7 years
Bridge Credit Agreement
Debt Instrument [Line Items]
Loan agreement entered date				Aug. 11, 2020
Two Thousand Eighteen Amended And Restated Credit Agreement
Debt Instrument [Line Items]
Loan agreement entered date				May 24, 2018
2018 Credit Agreement
Debt Instrument [Line Items]
Debt instrument, payment terms				7 years
Revolving Loans
Debt Instrument [Line Items]
Debt, variable interest rate							2.50%
Revolving Loans | LIBOR
Debt Instrument [Line Items]
Debt, variable interest rate							3.50%
First Lien Credit Agreement
Debt Instrument [Line Items]
Days of interest period							30 days
Percentage of amount greater than equal to 50% of aggregate amount of revolving commitments							0.35%
Percentage of daily amount of unused revolving commitments							50.00%
Percentage of amount less than 50% of aggregate amount of revolving commitments							0.25%
Debt instrument, variable rate description							Amounts borrowed under the First Lien Credit Agreement may be either Base Rate Loans or LIBOR Loans. Base Rate Loans bear interest at the highest of (a) the Prime Rate, (b) the Federal Funds Rate plus 0.50% and (c) the LIBOR Market Index Rate plus 1.0%, provided that the Base Rate will not be less than 1.50% per annum, in each case plus (w) for revolving loans, 2.50% per annum, and (x) for term loans, 4.74% per annum. LIBOR Loans bear interest at LIBOR plus (y) for revolving loans, 3.50% per annum, and (z) for term loans, 5.74% per annum, in each case, provided that LIBOR will not be less than 0.50% per annum. Interest is due to be paid in cash on the last day of each applicable interest period (with rolling 30-day interest periods) and on the Maturity Date. We are required to pay certain fees to the administrative agent for the account of the lenders in connection with the First Lien Credit Agreement, including an unused fee for the account of the revolving lenders, which will accrue (i) 0.35% per annum on the daily amount of the unused revolving commitments when that amount is greater than or equal to 50% of the aggregate amount of revolving commitments, and (ii) 0.25% when that amount is less than 50% of the aggregate amount of revolving commitments. Accrued and unpaid unused fees will be payable quarterly in arrears during the term of the First Lien Credit Agreement and on the Revolving Termination Date (or any earlier date of termination of the revolving commitments or reduction of the revolving commitments to zero).
First Lien Credit Agreement | LIBOR | Maximum
Debt Instrument [Line Items]
Debt, variable interest rate							0.50%
First Lien Credit Agreement | Term Loans
Debt Instrument [Line Items]
Debt, variable interest rate							4.74%
First Lien Credit Agreement | Term Loans | LIBOR
Debt Instrument [Line Items]
Debt, variable interest rate							5.74%
Second Lien Credit Agreement
Debt Instrument [Line Items]
Debt instrument, payment terms							7 years
Days of interest period							30 days
Debt instrument, variable rate description							Amounts borrowed under the Second Lien Credit Agreement may be either Base Rate Loans or LIBOR Loans. Base Rate Loans bear interest at the highest of (a) the Prime Rate, (b) the Federal Funds Rate plus 0.50% and (c) the LIBOR Market Index Rate plus 1.0%, provided that the Base Rate will not be less than 1.50% per annum, in each case plus 7.00% per annum. LIBOR Loans bear interest at LIBOR plus 8.00% per annum, provided that LIBOR will not be less than 0.50% per annum. Interest is due to be paid in kind on the last day of each applicable interest period (with rolling 30-day interest periods) by adding the accrued and unpaid amount thereof to the principal balance of the loans under the Second Lien Credit Agreement and then accruing interest on the increased principal amount (provided that after the discharge of our Senior Debt Obligations, interest will be paid in cash). We are required to pay certain fees to the administrative agent for the account of the lenders in connection with the Second Lien Credit Agreement.
First Amendment
Debt Instrument [Line Items]
Debt instrument waiver of default interest			$ 5,300,000
Principal amount of loans outstanding				$ 535,200,000