Quarterly report pursuant to Section 13 or 15(d)

Schedule of Related Party Transactions, by Related Party (Details)

v3.10.0.1
Schedule of Related Party Transactions, by Related Party (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Dec. 31, 2017
Related Party Transaction [Line Items]          
Management fees $ (5,041) $ 10,146 $ 18,120 $ 29,801  
Compensation costs related to restricted common stock 3,400 3,500 9,800 11,700  
Equity securities, at fair value 0   0   $ 29,413
PRCM Advisers LLC [Member]          
Related Party Transaction [Line Items]          
Management fees 12,400 10,100 $ 35,600 29,800  
Percent per annum of equity used to calculate management fees     1.50%    
Percent per annum of additional equity used to calculate management fees     0.75%    
One Time Downward Adjustment of Management Fees Payable     $ 15,000    
Maximum Additional One Time Downward Adjustment of Management Fees Payable     3,300    
Total One Time Downward Adjustment of Management Fees Payable     17,500    
Direct and allocated costs incurred by manager $ 5,300 $ 4,800 $ 16,100 $ 13,100  
Granite Point Mortgage Trust Inc. [Member]          
Related Party Transaction [Line Items]          
Purchases of equity securities of related party (in shares)     1,658,008    
Purchases of equity securities of related party     $ 30,000    
Equity securities, at fair value         29,400
Equity securities, unrealized gain (loss)         $ (600)
Proceeds from sales of equity securities of related party     31,200    
Realized gain on sales of equity securities of related party     $ 1,200