v3.26.1
Debt Obligations - Schedule of Debt (Details) - USD ($)
 6 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Debt Instrument [Line Items]    
Outstanding Principal $ 3,030,626,000  
Unamortized debt issuance costs $ 5,283,000 $ 5,887,000
Minimum    
Debt Instrument [Line Items]    
Weighted average life (years) 1 year 2 months 12 days  
Maximum    
Debt Instrument [Line Items]    
Weighted average life (years) 1 year 10 months 24 days  
Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size $ 5,647,423,000  
Outstanding Principal 3,030,626,000  
Carrying value $ 3,024,096,000  
Weighted average funding cost 5.70%  
Secured financing agreements, net | Commercial Real Estate Loans    
Debt Instrument [Line Items]    
Unamortized debt issuance costs $ 6,500,000 8,400,000
Secured Financing Agreements | Secured financing agreements, net    
Debt Instrument [Line Items]    
Carrying value 3,024,096,000 2,862,689,000
Secured Financing Agreements | KREF Lending IX | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 267,998,000  
Outstanding Principal 262,735,000  
Carrying value $ 262,659,000 271,455,000
Weighted average funding cost 5.70%  
Outstanding Principal $ 368,274,000  
Carrying value 367,867,000  
Secured Financing Agreements | KREF Lending XV | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 300,000,000  
Outstanding Principal 175,360,000  
Carrying value $ 174,619,000 237,422,000
Weighted average funding cost 5.30%  
Outstanding Principal $ 219,200,000  
Carrying value 216,130,000  
Secured Financing Agreements | KREF Lending XVI | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 129,000,000  
Outstanding Principal 129,000,000.0  
Carrying value $ 127,949,000 99,083,000
Weighted average funding cost 5.50%  
Outstanding Principal $ 161,250,000  
Carrying value 158,656,000  
Secured Financing Agreements | KREF Lending XIX - GBP | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 130,643,000  
Outstanding Principal 126,196,000  
Carrying value $ 125,836,000 0
Weighted average funding cost 5.20%  
Outstanding Principal $ 174,064,000  
Carrying value 170,727,000  
Secured Financing Agreements | KREF Lending XVII | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 250,000,000  
Outstanding Principal 94,407,000  
Carrying value $ 93,382,000 89,178,000
Weighted average funding cost 5.30%  
Outstanding Principal $ 122,151,000  
Carrying value 119,560,000  
Secured Financing Agreements | BMO Facility | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 300,000,000  
Outstanding Principal 71,126,000  
Carrying value $ 71,086,000 71,063,000
Weighted average funding cost 5.40%  
Outstanding Principal $ 90,795,000  
Carrying value 90,047,000  
Secured Financing Agreements | KREF Lending XII | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 150,000,000  
Outstanding Principal 0  
Carrying value $ 0 0
Weighted average funding cost 0.00%  
Outstanding Principal $ 0  
Carrying value 0  
Secured Financing Agreements | HSBC Facility | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 250,000,000  
Outstanding Principal 0  
Carrying value $ 0 0
Weighted average funding cost 0.00%  
Outstanding Principal $ 0  
Carrying value 0  
Secured Financing Agreements | KREF Lending XIII | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 265,625,000  
Outstanding Principal 195,198,000  
Carrying value $ 195,107,000 194,678,000
Weighted average funding cost 7.00%  
Outstanding Principal $ 229,644,000  
Carrying value 183,066,000  
Secured Financing Agreements | KREF Lending XX - EUR | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 131,282,000  
Outstanding Principal 114,486,000  
Carrying value $ 113,864,000 0
Weighted average funding cost 4.40%  
Outstanding Principal $ 134,690,000  
Carrying value 131,765,000  
Secured Financing Agreements | KREF Lending XIV | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 125,000,000  
Outstanding Principal 83,955,000  
Carrying value $ 83,835,000 79,780,000
Weighted average funding cost 6.80%  
Outstanding Principal $ 110,544,000  
Carrying value 109,629,000  
Secured Financing Agreements | KREF Lending XI | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 0  
Outstanding Principal 0  
Carrying value $ 0 90,000,000
Weighted average funding cost 0.00%  
Outstanding Principal $ 0  
Carrying value 0  
Secured Financing Agreements | Wells Fargo | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 600,000,000  
Outstanding Principal 401,931,000  
Carrying value $ 401,244,000 578,569,000
Weighted average funding cost 5.50%  
Outstanding Principal $ 595,573,000  
Carrying value 592,493,000  
Secured Financing Agreements | Morgan Stanley | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 500,000,000  
Outstanding Principal 277,528,000  
Carrying value $ 277,523,000 308,388,000
Weighted average funding cost 5.80%  
Outstanding Principal $ 495,699,000  
Carrying value 454,656,000  
Secured Financing Agreements | Morgan Stanley - GBP/EUR | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 397,875,000  
Outstanding Principal 159,582,000  
Carrying value $ 158,605,000 160,725,000
Weighted average funding cost 4.80%  
Outstanding Principal $ 212,776,000  
Carrying value 209,032,000  
Secured Financing Agreements | Goldman Sachs | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 150,000,000  
Outstanding Principal 78,433,000  
Carrying value $ 77,939,000 169,451,000
Weighted average funding cost 6.10%  
Outstanding Principal $ 179,996,000  
Carrying value 169,772,000  
Term Loan Facility | KREF Lending VII | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size 1,000,000,000  
Outstanding Principal 510,689,000  
Carrying value $ 510,448,000 512,897,000
Weighted average funding cost 5.70%  
Outstanding Principal $ 664,818,000  
Carrying value $ 621,302,000  
Weighted average life (years) 5 years  
Extension term 2 years  
Revolving Credit Agreement | Secured financing agreements, net    
Debt Instrument [Line Items]    
Maximum Facility Size $ 700,000,000  
Outstanding Principal 350,000,000  
Carrying value $ 350,000,000 $ 0
Weighted average funding cost 5.90%  
Deferred financing/debt issuance costs $ 5,300,000