Related Party and Affiliated Real Estate Joint Venture Transactions - Summarized Information of Receivables from Related Party and Affiliated Joint Ventures (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Other Related Party Transactions [Line Items]
Receivables from related parties and affiliated real estate joint ventures	$ 2,847	$ 16,611
Mortgage notes receivable
Schedule of Other Related Party Transactions [Line Items]
Receivables from related parties and affiliated real estate joint ventures	0	15,860
Other receivables from stores
Schedule of Other Related Party Transactions [Line Items]
Receivables from related parties and affiliated real estate joint ventures	$ 2,847	$ 751