Summary of Difference Between Fair Value of Consideration Transferred and Carrying Amount of Shares that were Redeemed and Exchanged (Detail) - USD ($) $ in Thousands						6 Months Ended
		Jun. 27, 2018	Mar. 19, 2018	Jun. 22, 2017	Dec. 07, 2016	Jun. 30, 2018	Jun. 26, 2018
Temporary Equity [Line Items]
Share repurchase, exchange fees		$ 418
Total consideration transferred in redemption and exchange		61,548
Net increase to equity as a result of redemption		11,932				$ 11,932
Preferred Series D
Temporary Equity [Line Items]
Liquidation preference of Series D preferred shares of RAIT prior to June 27, 2018							$ 73,480
Cash received for sale of RAIT IV's interests in Holdings 2016 and Holdings 2017		54,632
Defined available cash held by RAIT IV		2,133
Total par amount of Series D preferred shares of RAIT redeemed		56,765	$ 4,863	$ 10,057	$ 11,600
7.75% Series A Cumulative Redeemable Preferred Stock
Temporary Equity [Line Items]
Total fair value of series preferred shares exchanged	[1]	2,498
8.375% Series B Cumulative Redeemable Preferred Stock
Temporary Equity [Line Items]
Total fair value of series preferred shares exchanged	[2]	1,091
8.875% Series C Cumulative Redeemable Preferred Stock
Temporary Equity [Line Items]
Total fair value of series preferred shares exchanged	[3]	776
Preferred Series A, B, and C
Temporary Equity [Line Items]
Total fair value of series preferred shares exchanged		$ 4,365

[1] Represents the fair value of 383,147 shares of Series A preferred that were issued to the Investor. The fair value is based upon $6.52 per share, which was the closing price of the Series A preferred shares on June 27, 2018.

[2] Represents the fair value of 167,828 shares of Series B preferred that were issued to the Investor. The fair value is based upon $6.50 per share, which was the closing price of the Series B preferred shares on June 27, 2018.

[3] Represents the fair value of 117,605 shares of Series C preferred that were issued to the Investor. The fair value is based upon $6.60 per share, which was the closing price of the Series C preferred shares on June 27, 2018.