Annual report [Section 13 and 15(d), not S-K Item 405]

BORROWINGS - Revolving Line of Credit Narrative (Details)

v3.26.1
BORROWINGS - Revolving Line of Credit Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Debt Instrument [Line Items]    
Indebtedness asset coverage on our senior securities 213.80% 204.40%
Credit Facility | Line of Credit    
Debt Instrument [Line Items]    
Unused fee percentage 1.00% 1.00%
Credit Facility | Revolving Line of Credit | Line of Credit    
Debt Instrument [Line Items]    
Commitment amount $ 300,000 $ 270,000
Debt instrument, variable rate floor 0.35% 0.35%
Debt instrument, basis spread on variable rate 2.90% 3.25%
Covenant, required minimum net worth of mandatory redeemable term preferred stock $ 210,000  
Covenant, required minimum net worth of mandatory redeemable term preferred stock, plus percent of all equity and subordinated debt raised 50.00%  
Covenant, required minimum net worth of mandatory redeemable term preferred stock, minus percent of any equity or subordinated debt redeemed or retired 50.00%  
Covenant, required minimum net worth of mandatory redeemable term preferred stock, plus percent of all equity and subordinated debt raised, minus percent of any equity or subordinated debt redeemed or retired $ 476,600  
Indebtedness asset coverage on our senior securities 213.80%  
Senior security, indebtedness, asset coverage amount $ 1,200,000  
Credit Facility | Revolving Line of Credit | Line of Credit | Minimum    
Debt Instrument [Line Items]    
Indebtedness asset coverage on our senior securities 150.00%  
Credit Facility | Revolving Line of Credit | Line of Credit | Less than or Equal to 50% of Commitment    
Debt Instrument [Line Items]    
Unused fee percentage 0.50%  
Credit Facility | Revolving Line of Credit | Line of Credit | Greater than 50% but Less than or Equal to 65% of Commitment    
Debt Instrument [Line Items]    
Unused fee percentage 0.75%  
Credit Facility | Revolving Line of Credit | Line of Credit | Greater Than 65% Of Commitment    
Debt Instrument [Line Items]    
Unused fee percentage 1.00%  
Credit Facility | Revolving Line of Credit | Line of Credit | Secured Overnight Financing Rate (SOFR), Adjustment    
Debt Instrument [Line Items]    
Debt instrument, basis spread on variable rate 0.10%  
Credit Facility | Revolving Line of Credit | Line of Credit | SOFR, Tranche One    
Debt Instrument [Line Items]    
Debt instrument, basis spread on variable rate 3.15%  
Credit Facility | Revolving Line of Credit | Line of Credit | SOFR, Tranche Two    
Debt Instrument [Line Items]    
Debt instrument, basis spread on variable rate 3.40%  
Credit Facility | Revolving Line of Credit | Line of Credit | SOFR, Thereafter    
Debt Instrument [Line Items]    
Debt instrument, basis spread on variable rate 3.65%