Quarterly report pursuant to Section 13 or 15(d)

Non-Controlling Interests - Summary Of Components of Non-Controlling Interests in Loss of Consolidated Entities (Detail)

v3.8.0.1
Non-Controlling Interests - Summary Of Components of Non-Controlling Interests in Loss of Consolidated Entities (Detail) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Dec. 31, 2016
Noncontrolling Interest [Line Items]          
Non-controlling interests in loss of consolidated entities $ (9,191) $ (3,975) $ (17,355) $ (12,324) $ (16,195)
Avenue [Member]          
Noncontrolling Interest [Line Items]          
Non-controlling interests in loss of consolidated entities $ (1,015) [1] $ (47) $ (1,329) $ (231) (349)
Non-controlling ownership 28.90% [1] 10.50% [2] 28.90% [1] 10.50% [2]  
Coronado SO Co, Inc [Member]          
Noncontrolling Interest [Line Items]          
Non-controlling interests in loss of consolidated entities $ (15) $ (4) $ (22) $ (14) (19)
Non-controlling ownership 13.00% 13.00% [2] 13.00% 13.00% [2]  
Mustang Therapeutics, Inc [Member]          
Noncontrolling Interest [Line Items]          
Non-controlling interests in loss of consolidated entities $ (3,241) [1] $ (204) $ (8,268) $ (363) (1,805)
Non-controlling ownership 58.70% [1] 10.00% [2] 58.70% [1] 10.00% [2]  
Checkpoint Therapeutics, Inc [Member]          
Noncontrolling Interest [Line Items]          
Non-controlling interests in loss of consolidated entities $ (3,437) [3] $ (3,254) $ (10,144) [3] $ (10,767) (11,733)
Non-controlling ownership [3] 61.90% 63.50% [2] 61.90% 63.50% [2]  
JMC [Member]          
Noncontrolling Interest [Line Items]          
Non-controlling interests in loss of consolidated entities $ (103) $ (104) $ (150) $ (333) (355)
Non-controlling ownership 6.90% 8.10% [2] 6.90% 8.10% [2]  
Helocyte [Member]          
Noncontrolling Interest [Line Items]          
Non-controlling interests in loss of consolidated entities $ (376) $ (362) $ (975) $ (616) (1,155)
Non-controlling ownership 20.00% 20.60% [2] 20.00% 20.60% [2]  
Cellvation [Member]          
Noncontrolling Interest [Line Items]          
Non-controlling interests in loss of consolidated entities $ 24   $ (60)   (158)
Non-controlling ownership 22.00%   22.00%    
National Holdings [Member]          
Noncontrolling Interest [Line Items]          
Non-controlling interests in loss of consolidated entities $ (27)   $ 4,845   $ (621)
Non-controlling ownership 43.40%   43.40%    
Caelum [Member]          
Noncontrolling Interest [Line Items]          
Non-controlling interests in loss of consolidated entities $ (835)   $ (1,086)    
Non-controlling ownership 25.20%   25.20%    
Aevitas [Member]          
Noncontrolling Interest [Line Items]          
Non-controlling interests in loss of consolidated entities $ (166)   $ (166)    
Non-controlling ownership 25.30%   25.30%    
[1] Mustang and Avenue are consolidated with Fortress’s operations because Fortress maintains voting control through its ownership of Mustang’s and Avenue’s Class A preferred shares which provide super-majority voting rights.
[2] Represents a weighted average of ownership during the periods presented
[3] Checkpoint is consolidated with Fortress’s operations because Fortress maintains voting control through its ownership of Checkpoint’s Class A common shares which provide for super-majority voting rights