| Cover | 12 Months Ended |
| Dec. 31, 2023 | |
| Document Information [Line Items] | |
| Document Type | PRE 14A |
| Amendment Flag | false |
| Entity Information [Line Items] | |
| Entity Registrant Name | Hercules Capital, Inc. |
| Entity Central Index Key | 0001280784 |
| Pay vs Performance Disclosure | 12 Months Ended | |||
| Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | |
| Pay vs Performance Disclosure | ||||
| Pay vs Performance Disclosure, Table | In accordance with the final rule adopted by the SEC in August 2022 implementing Section 953(a) of the Dodd-Frank Act, we are providing the following table that sets forth certain compensation measures for certain of our officers alongside certain performance metrics for the Company and certain of its industry peers: Value of Initial $100 Year Summary Compensation (1) Average SCT Non-CEO Average Non-CEO (1) Company Peer Group (2) Net ($ in Return on 2023 8,891,994 11,871,291 1,778,104 2,234,447 187.59 128.90 337,484 14.9 % 2022 7,370,508 12,508,448 1,441,832 1,354,862 131.26 113.50 102,081 11.6 % 2021 7,410,986 11,960,041 1,548,309 1,560,941 145.05 125.26 174,155 11.1 % 2020 7,871,404 12,662,414 1,621,547 1,676,816 115.13 91.15 227,261 11.3 % — 2022 and 2023 CEO is Bluestein; non-CEO — 2021 CEO is Bluestein; non-CEO — 2020 CEO is Bluestein; non-CEO (1) The amounts shown for Compensation Actually S-K Name Year SCT SCT Stock Fair Change Fair Change Fair Value of Compensation PEO 2023 8,891,994 5,019,494 7,102,637 576,741 - 319,413 - - 11,871,291 2022 7,370,508 (3,700,008 ) 3,211,607 (126,779 ) - 5,753,121 - - 12,508,448 2021 7,410,986 (3,449,995 ) 4,289,439 2,843,025 - 866,586 - - 11,960,041 2020 7,871,404 (3,989,493 ) 4,454,699 4,439,836 - (114,033 ) - - 12,662,414 NEO Average 2023 1,778,104 818,104 1,149,198 82,349 - 42,900 - - 2,234,447 2022 1,441,832 (541,665 ) 470,981 (20,807 ) - 4,521 - - 1,354,862 2021 1,548,309 (611,752 ) 676,676 7,210 - 65,068 (124,571 ) - 1,560,941 2020 1,621,547 (602,500 ) 672,756 21,233 - (36,220 ) - - 1,676,816 (2) “Peer Group” TSR is the S&P500 BDC Index | |||
| Company Selected Measure Name | Return on Equity | |||
| Named Executive Officers, Footnote | Meyer, Botelho and Follmann | Meyer, Botelho and Follmann | Meyer and Grace | Meyer and Grace |
| Peer Group Issuers, Footnote | “Peer Group” TSR is the S&P500 BDC Index | |||
| PEO Total Compensation Amount | $ 8,891,994 | $ 7,370,508 | $ 7,410,986 | $ 7,871,404 |
| PEO Actually Paid Compensation Amount | $ 11,871,291 | 12,508,448 | 11,960,041 | 12,662,414 |
| Adjustment To PEO Compensation, Footnote | (1) The amounts shown for Compensation Actually S-K Name Year SCT SCT Stock Fair Change Fair Change Fair Value of Compensation PEO 2023 8,891,994 5,019,494 7,102,637 576,741 - 319,413 - - 11,871,291 2022 7,370,508 (3,700,008 ) 3,211,607 (126,779 ) - 5,753,121 - - 12,508,448 2021 7,410,986 (3,449,995 ) 4,289,439 2,843,025 - 866,586 - - 11,960,041 2020 7,871,404 (3,989,493 ) 4,454,699 4,439,836 - (114,033 ) - - 12,662,414 NEO Average 2023 1,778,104 818,104 1,149,198 82,349 - 42,900 - - 2,234,447 2022 1,441,832 (541,665 ) 470,981 (20,807 ) - 4,521 - - 1,354,862 2021 1,548,309 (611,752 ) 676,676 7,210 - 65,068 (124,571 ) - 1,560,941 2020 1,621,547 (602,500 ) 672,756 21,233 - (36,220 ) - - 1,676,816 | |||
| Non-PEO NEO Average Total Compensation Amount | $ 1,778,104 | 1,441,832 | 1,548,309 | 1,621,547 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 2,234,447 | 1,354,862 | 1,560,941 | 1,676,816 |
| Adjustment to Non-PEO NEO Compensation Footnote | (1) The amounts shown for Compensation Actually S-K Name Year SCT SCT Stock Fair Change Fair Change Fair Value of Compensation PEO 2023 8,891,994 5,019,494 7,102,637 576,741 - 319,413 - - 11,871,291 2022 7,370,508 (3,700,008 ) 3,211,607 (126,779 ) - 5,753,121 - - 12,508,448 2021 7,410,986 (3,449,995 ) 4,289,439 2,843,025 - 866,586 - - 11,960,041 2020 7,871,404 (3,989,493 ) 4,454,699 4,439,836 - (114,033 ) - - 12,662,414 NEO Average 2023 1,778,104 818,104 1,149,198 82,349 - 42,900 - - 2,234,447 2022 1,441,832 (541,665 ) 470,981 (20,807 ) - 4,521 - - 1,354,862 2021 1,548,309 (611,752 ) 676,676 7,210 - 65,068 (124,571 ) - 1,560,941 2020 1,621,547 (602,500 ) 672,756 21,233 - (36,220 ) - - 1,676,816 | |||
| Compensation Actually Paid vs. Total Shareholder Return | The graph below reflects the relationship between “Compensation Actually Paid” to our CEO and other NEOs and TSR for the Company and the S&P BDC Index: | |||
| Compensation Actually Paid vs. Net Income | The graph below reflects the relationship between “Compensation Actually Paid” to our CEO and other NEOs and Net Investment Income: | |||
| Compensation Actually Paid vs. Company Selected Measure | The graph below reflects the relationship between “Compensation Actually Paid” to our CEO and other NEOs and the Company Selected Performance Measure of ROE for the Company: | |||
| Total Shareholder Return Vs Peer Group | The graph below reflects the relationship between “Compensation Actually Paid” to our CEO and other NEOs and TSR for the Company and the S&P BDC Index: | |||
| Tabular List, Table | As described above, restrictions imposed by the 1940 Act restrict the Compensation Committee’s ability to use nondiscretionary or formulaic Company performance goals or criteria to determine executive incentive compensation. The Compensation Committee instead considers several financial performance metrics, along with other factors including operational goals and individual performance criteria, in determining the appropriate compensation for the NEOs. Subject to the foregoing restrictions imposed by the 1940 Act, in the Company’s assessment, the following list of performance measures represent the most important performance measures used to link compensation actually paid to our NEOs, for the most recently completed fiscal year, to Company performance: • return on equity (ROE); • total dividends paid to stockholders; • net realized gain or losses; and • net unrealized appreciation or depreciation. | |||
| Total Shareholder Return Amount | $ 187.59 | 131.26 | 145.05 | 115.13 |
| Peer Group Total Shareholder Return Amount | 128.9 | 113.5 | 125.26 | 91.15 |
| Net Income (Loss) | $ 337,484,000 | $ 102,081,000 | $ 174,155,000 | $ 227,261,000 |
| Company Selected Measure Amount | 0.149 | 0.116 | 0.111 | 0.113 |
| PEO Name | Bluestein | Bluestein | Bluestein | Bluestein |
| Measure:: 1 | ||||
| Pay vs Performance Disclosure | ||||
| Name | return on equity (ROE) | |||
| Measure:: 2 | ||||
| Pay vs Performance Disclosure | ||||
| Name | total dividends paid to stockholders | |||
| Measure:: 3 | ||||
| Pay vs Performance Disclosure | ||||
| Name | net realized gain or losses | |||
| Measure:: 4 | ||||
| Pay vs Performance Disclosure | ||||
| Name | net unrealized appreciation or depreciation | |||
| PEO | SCT Stock Awards [Member] | ||||
| Pay vs Performance Disclosure | ||||
| Adjustment to Compensation, Amount | $ 5,019,494 | $ (3,700,008) | $ (3,449,995) | $ (3,989,493) |
| PEO | Fair Value of Stock Awards Granted in the Covered Year [Member] | ||||
| Pay vs Performance Disclosure | ||||
| Adjustment to Compensation, Amount | 7,102,637 | 3,211,607 | 4,289,439 | 4,454,699 |
| PEO | Change in Fair Value of Unvested Stock Awards from Prior Years [Member] | ||||
| Pay vs Performance Disclosure | ||||
| Adjustment to Compensation, Amount | 576,741 | (126,779) | 2,843,025 | 4,439,836 |
| PEO | Change in Fair Value of Stock Awards from Prior Years that Vested in the Covered Year [Member] | ||||
| Pay vs Performance Disclosure | ||||
| Adjustment to Compensation, Amount | 319,413 | 5,753,121 | 866,586 | (114,033) |
| Non-PEO NEO | SCT Stock Awards [Member] | ||||
| Pay vs Performance Disclosure | ||||
| Adjustment to Compensation, Amount | 818,104 | (541,665) | (611,752) | (602,500) |
| Non-PEO NEO | Fair Value of Stock Awards Granted in the Covered Year [Member] | ||||
| Pay vs Performance Disclosure | ||||
| Adjustment to Compensation, Amount | 1,149,198 | 470,981 | 676,676 | 672,756 |
| Non-PEO NEO | Change in Fair Value of Unvested Stock Awards from Prior Years [Member] | ||||
| Pay vs Performance Disclosure | ||||
| Adjustment to Compensation, Amount | 82,349 | (20,807) | 7,210 | 21,233 |
| Non-PEO NEO | Change in Fair Value of Stock Awards from Prior Years that Vested in the Covered Year [Member] | ||||
| Pay vs Performance Disclosure | ||||
| Adjustment to Compensation, Amount | $ 42,900 | $ 4,521 | 65,068 | $ (36,220) |
| Non-PEO NEO | Fair Value of Stock Awards Forfeited [Member] | ||||
| Pay vs Performance Disclosure | ||||
| Adjustment to Compensation, Amount | $ (124,571) | |||
