XML 66 R51.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Borrowings - Additional information (Details) € in Millions, £ in Millions, kr in Millions |  | 1 Months Ended | 12 Months Ended |  |  |  |  |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Nov. 23, 2021 USD ($) | Feb. 28, 2019 USD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2023 SEK (kr) | Dec. 31, 2023 GBP (£) | Dec. 31, 2023 EUR (€) | Dec. 31, 2022 SEK (kr) | Dec. 31, 2022 GBP (£) | Dec. 31, 2022 EUR (€) | Apr. 30, 2022 USD ($) | Apr. 01, 2022 USD ($) | Feb. 25, 2022 USD ($) | Nov. 04, 2021 USD ($) | Feb. 25, 2021 USD ($) | Nov. 04, 2020 USD ($) | Sep. 29, 2020 USD ($) | Sep. 24, 2020 USD ($) | Aug. 03, 2020 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowings under credit facilities |  |  | $ 719,914,000 | $ 729,144,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment aggregate amount |  | $ 800,000,000 | $ 1,100,000,000 | 1,100,000,000 |  |  |  |  |  |  |  | $ 1,100,000,000 | $ 965,000,000 | $ 875,000,000 |  |  |  |  |
Line of credit facility commitment aggregate value |  | $ 1,200,000,000 |  |  |  |  |  |  |  |  |  | $ 1,500,000,000 | $ 1,500,000,000 |  |  |  |  |  |
Debt instrument, basis spread on variable floor rate (as percent) |  | 1.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of unused portion of credit facility, greater than two-third of commitments (as percent) |  | 0.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of unused portion of credit facility, less than two-third of commitments (as percent) |  | 0.375% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt issuance costs, financing fees |  | $ 6,400,000 |  |  |  |  |  |  |  |  | $ 4,100,000 |  |  |  |  |  |  |  |
Effective interest rate |  |  | 7.09% |  | 7.09% | 7.09% | 7.09% |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Line of Credit | Level 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of long-term debt |  |  | $ 719,900,000 | 729,100,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Line of Credit | Interest Period Of One Month |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, credit spread adjustment |  | 0.0010 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Line of Credit | Interest Period Of Three Month |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, credit spread adjustment |  | 0.0015 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Line of Credit | Interest Period Of Six Month |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, credit spread adjustment |  | 0.0025 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Federal Funds Purchased | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  | 0.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Base Rate | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  | 1.25% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Base Rate | Line of Credit | External Credit Rating, Investment Grade |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  | 1.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | SOFR | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  | 2.25% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | SOFR | Line of Credit | External Credit Rating, Investment Grade |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  | 2.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Applicable Rate | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  | 2.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Applicable Rate | Line of Credit | External Credit Rating, Non Investment Grade |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  | 2.25% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Screen Rate | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  | 2.20% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Screen Rate | Line of Credit | External Credit Rating, Non Investment Grade |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  | 2.45% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | Overnight Bank Funding Rate | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  | 0.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 2019 Credit Facility | One-Month Secured Overnight Financing Rate (SOFR) | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  | 1.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, credit spread adjustment |  | 0.0010 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Denominated In U.S Dollars | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowings under credit facilities |  |  | $ 489,500,000 | $ 497,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Effective interest rate |  |  | 7.428% | 6.324% | 7.428% | 7.428% | 7.428% | 6.324% | 6.324% | 6.324% |  |  |  |  |  |  |  |  |
Debt Denominated In U.S Dollars | LIBOR | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  |  |  | 4.224% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Denominated In U.S Dollars | One-Month Secured Overnight Financing Rate (SOFR) | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  |  | 5.328% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Denominated In Swedish Kronas | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowings under credit facilities |  |  | $ 1,300,000 | $ 1,200,000 | kr 12.8 |  |  | kr 12.8 |  |  |  |  |  |  |  |  |  |  |
Effective interest rate |  |  | 6.063% | 4.375% | 6.063% | 6.063% | 6.063% | 4.375% | 4.375% | 4.375% |  |  |  |  |  |  |  |  |
Debt Denominated In Swedish Kronas | Stockholm Interbank Offered Rate (STIBOR) | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  |  | 4.063% | 2.375% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Denominated In British Pounds | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowings under credit facilities |  |  | $ 84,900,000 | $ 82,500,000 |  | £ 66.6 |  |  | £ 68.6 |  |  |  |  |  |  |  |  |  |
Effective interest rate |  |  | 7.22% | 4.96% | 7.22% | 7.22% | 7.22% | 4.96% | 4.96% | 4.96% |  |  |  |  |  |  |  |  |
Debt Denominated In British Pounds | Sterling Overnight Index Average (SONIA) | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  |  | 5.22% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Denominated In British Pounds | GBP LIBOR | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  |  |  | 0.296% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Denominated In Euro | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowings under credit facilities |  |  | $ 144,300,000 | $ 147,900,000 |  |  | € 130.6 |  |  | € 138.6 |  |  |  |  |  |  |  |  |
Effective interest rate |  |  | 5.875% | 3.625% | 5.875% | 5.875% | 5.875% | 3.625% | 3.625% | 3.625% |  |  |  |  |  |  |  |  |
Debt Denominated In Euro | Euro Interbank Offered Rate (EURIBOR) | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  |  | 3.875% | 1.625% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
September 24, 2020 - August 2025 Notes | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 25,000,000 | $ 25,000,000 | $ 50,000,000
Fixed interest rate |  |  | 4.66% |  | 4.66% | 4.66% | 4.66% |  |  |  |  |  |  |  |  |  |  |  | 4.66%
Ownership percent for immediate conversion |  |  | 66.67% |  | 66.67% | 66.67% | 66.67% |  |  |  |  |  |  |  |  |  |  |  |
September 24, 2020 - August 2025 Notes | Notes | Level 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of long-term debt |  |  | $ 47,800,000 | $ 46,100,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
November 5, 2020 - Series B Notes | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 62,500,000 |  |  |
Fixed interest rate |  |  | 4.25% |  | 4.25% | 4.25% | 4.25% |  |  |  |  |  |  |  |  | 4.25% |  |  |
November 5, 2020 - Series B Notes | Notes | Level 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of long-term debt |  |  | $ 59,300,000 | 56,800,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
November 5, 2020 - Series C Notes | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 112,500,000 |  |  |
Fixed interest rate |  |  | 4.75% |  | 4.75% | 4.75% | 4.75% |  |  |  |  |  |  |  |  | 4.75% |  |  |
November 5, 2020 - Series C Notes | Notes | Level 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of long-term debt |  |  | $ 102,500,000 | 97,700,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Series B And Series C Senior Unsecured Notes Due November | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate extended |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.0075 |  |  |
Investment grade conditions |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.0150 |  |  |
February 25, 2021 Series D Notes | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 80,000,000 |  |  |  |
Fixed interest rate |  |  | 3.41% |  | 3.41% | 3.41% | 3.41% |  |  |  |  |  |  |  | 3.41% |  |  |  |
February 25, 2021 Series D Notes | Notes | Level 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of long-term debt |  |  | $ 73,400,000 | 69,600,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
February 25, 2021 Series E Notes | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 70,000,000 |  |  |  |
Fixed interest rate |  |  | 4.06% |  | 4.06% | 4.06% | 4.06% |  |  |  |  |  |  |  | 4.06% |  |  |  |
February 25, 2021 Series E Notes | Notes | Level 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of long-term debt |  |  | $ 61,200,000 | 57,800,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Series D And Series E Senior Unsecured Notes Due February | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate extended |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.0075 |  |  |  |
Investment grade conditions |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.0150 |  |  |  |
November 23, 2021 - November 2026 Notes | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount | $ 350,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fixed interest rate | 3.30% |  | 3.30% |  | 3.30% | 3.30% | 3.30% |  |  |  |  |  |  |  |  |  |  |  |
Ownership percent for immediate conversion |  |  | 66.67% |  | 66.67% | 66.67% | 66.67% |  |  |  |  |  |  |  |  |  |  |  |
Redemption percentage on purchase price (as percent) | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
November 23, 2021 - November 2026 Notes | Notes | Level 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of long-term debt |  |  | $ 311,400,000 | $ 294,600,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

X
- Definition Debt Instrument, Credit Spread Adjustment + References No definition available. + Details
Name: | bbdc_DebtInstrumentCreditSpreadAdjustment
Namespace Prefix: | bbdc_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Debt Instrument, Ownership Percentage For Immediate Conversion + References No definition available. + Details
Name: | bbdc_DebtInstrumentOwnershipPercentageForImmediateConversion
Namespace Prefix: | bbdc_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Debt Instrument, Variable Interest Rate, Floor + References No definition available. + Details
Name: | bbdc_DebtInstrumentVariableInterestRateFloor
Namespace Prefix: | bbdc_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of credit facility, accordion feature, increase limit, subject to certain conditions by obtaining additional commitments from existing and/or new lenders. + References No definition available. + Details
Name: | bbdc_LineOfCreditFacilityAccordionFeatureAggregateLimit
Namespace Prefix: | bbdc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line Of Credit Facility, Unused Capacity, Less Than Two-Thirds Of Commitment Fee Percentage + References No definition available. + Details
Name: | bbdc_LineOfCreditFacilityUnusedCapacityLessThanTwoThirdsOfCommitmentFeePercentage
Namespace Prefix: | bbdc_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of Credit Interest Rate Increase + References No definition available. + Details
Name: | bbdc_LineOfCreditInterestRateStepUpIncreasePursuantToInvestmentGradeConditions
Namespace Prefix: | bbdc_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line Of Credit, Interest Rate Step Up To Increase Pursuant To Debt To Total Assets Threshold + References No definition available. + Details
Name: | bbdc_LineOfCreditInterestRateStepUpToIncreasePursuantToDebtToTotalAssetsThreshold
Namespace Prefix: | bbdc_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482900/835-30-50-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69B -Publisher FASB -URI https://asc.fasb.org//1943274/2147481568/470-20-55-69B Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69C -Publisher FASB -URI https://asc.fasb.org//1943274/2147481568/470-20-55-69C Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482925/835-30-45-2 Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482949/835-30-55-8 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482900/835-30-50-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482925/835-30-45-2 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-6 + Details
Name: | us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482900/835-30-50-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(f)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04(a)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480678/235-10-S99-3 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B Reference 5: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69B -Publisher FASB -URI https://asc.fasb.org//1943274/2147481568/470-20-55-69B Reference 6: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69C -Publisher FASB -URI https://asc.fasb.org//1943274/2147481568/470-20-55-69C Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69E -Publisher FASB -URI https://asc.fasb.org//1943274/2147481568/470-20-55-69E Reference 8: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69F -Publisher FASB -URI https://asc.fasb.org//1943274/2147481568/470-20-55-69F Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B Reference 11: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (h) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1D -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1D Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1D -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1D Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1D -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1D Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1E -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1E -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1E -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1F Reference 22: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1F Reference 23: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1F Reference 24: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1F Reference 25: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1I -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I + Details
Name: | us-gaap_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage price of original principal amount of debt at which debt can be redeemed by the issuer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph e -SubTopic 470 -Topic 942 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480848/942-470-50-3 + Details
Name: | us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, before accumulated amortization, of debt issuance costs related to line of credit arrangements. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section S45 -Paragraph 1 -SubTopic 30 -Topic 835 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479359/835-30-S45-1 + Details
Name: | us-gaap_DebtIssuanceCostsLineOfCreditArrangementsGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -SubTopic 10 -Topic 210 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1 + Details
Name: | us-gaap_LineOfCredit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility. + References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. + References No definition available. + Details
Name: | us-gaap_LongTermDebtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_February2019CreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | bbdc_InterestPeriodAxis=bbdc_InterestPeriodOfOneMonthMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | bbdc_InterestPeriodAxis=bbdc_InterestPeriodOfThreeMonthMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | bbdc_InterestPeriodAxis=bbdc_InterestPeriodOfSixMonthMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=us-gaap_FederalFundsPurchasedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExternalCreditRatingByGroupingAxis=us-gaap_ExternalCreditRatingInvestmentGradeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=bbdc_SecuredOvernightFinancingRateSOFRMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=bbdc_ApplicableRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExternalCreditRatingByGroupingAxis=us-gaap_ExternalCreditRatingNonInvestmentGradeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=bbdc_ScreenRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=bbdc_OvernightBankFundingRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=bbdc_OneMonthSecuredOvernightFinancingRateSOFRMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_BorrowingsDenominatedInUSDollarsUnderFebruary2019CreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=bbdc_LondonInterbankOfferedRateLIBOR1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_BorrowingsDenominatedInSwedishKronasunderFebruary2019CreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=bbdc_StockholmInterbankOfferedRateSTIBORMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_BorrowingsDenominatedInBritishPoundsunderFebruary2019CreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=bbdc_SterlingOvernightIndexAverageSONIAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=bbdc_GBPLIBORMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_BorrowingsDenominatedInEurounderFebruary2019CreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=bbdc_EuroInterbankOfferedRateEURIBORMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_SeriesASeniorUnsecuredNotesDueAugust2025Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_SeriesBSeniorUnsecuredNotesDueNovember2025Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_SeriesCSeniorUnsecuredNotesDueNovember2027Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_SeriesBAndSeriesCSeniorUnsecuredNotesDueNovemberMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_SeriesDSeniorUnsecuredNotesDueFebruary2026Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_SeriesESeniorUnsecuredNotesDueFebruary2028Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_SeriesDAndSeriesESeniorUnsecuredNotesDueFebruaryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbdc_November2026NotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |