Investment in and Advances to Affiliate - Schedule of Revenue From Contracts With Customers Included in Fee and Other Income on Consolidated Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation Of Revenue [Line Items]
Total revenue from contracts with RVI	$ 14,747	$ 16,585
Retail Value Inc. [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from contracts with RVI	7,600	9,500
Asset and Property Management Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from contracts with RVI	9,325	11,531
Asset and Property Management Fees [Member] | Retail Value Inc. [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from contracts with RVI	4,800	5,800
Leasing Commissions [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from contracts with RVI	2,996	1,499
Leasing Commissions [Member] | Retail Value Inc. [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from contracts with RVI	1,200	800
Disposition Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from contracts with RVI	1,556	1,202
Disposition Fees [Member] | Retail Value Inc. [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from contracts with RVI	1,600	1,100
Credit Facility Guaranty and Refinancing Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from contracts with RVI	0	1,800
Credit Facility Guaranty and Refinancing Fees [Member] | Retail Value Inc. [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from contracts with RVI	$ 0	$ 1,800