Investment In and Advances to Affiliate - Additional Information (Detail) - Retail Value Inc. [Member] - USD ($)		3 Months Ended
	Jul. 01, 2018	Sep. 30, 2018
Investments In And Advances To Affiliates [Line Items]
Receivable from affiliate consist of insurance receivable and restricted cash		$ 36,500,000
Repayment from affiliate		$ 3,100,000
Series A Preferred Stock [Member]
Investments In And Advances To Affiliates [Line Items]
Cumulative redeemable preferred shares, shares issued	1,000
Preferred stock dividend rate	0.00%
Series A Preferred Stock [Member] | Aggregate Gross Proceeds of RVI's Asset Sales Subsequent to July 1, 2018 Exceeds $2.0 Billion [Member]
Investments In And Advances To Affiliates [Line Items]
Preferred stock, value	$ 190,000,000
Maximum increase in preferred stock amount	10,000,000
Threshold limit for proceeds from sale of real estate investment property	$ 2,000,000,000
Series A Preferred Stock [Member] | To Redeem RVI Preferred Shares Upon Aggregate Dividends Payments Equalling $200 Million [Member]
Investments In And Advances To Affiliates [Line Items]
Preferred stock, redemption price	$ 1.00
Series A Preferred Stock [Member] | Maximum [Member] | To Redeem RVI Preferred Shares Upon Aggregate Dividends Payments Equalling $200 Million [Member]
Investments In And Advances To Affiliates [Line Items]
Preferred stock, value	$ 200,000,000