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v3.22.4

Net Assets - Roll forward of Net Assets (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
Investment Company, Net Assets [Roll Forward] |  |  |
Beginning of the period (in shares) | 97,907,441 |  |
Beginning of the period | $ 1,342,612 | $ 1,236,889 | $ 1,283,468
Issuances of common stock | 41,104 | 14,655 |
Offering costs | (222) | (231) |
Distributions declared | (131,955) | (117,675) | (120,792)
Purchase of non-controlling interest in NMNLC |  |  | 12,376
Contributions related to non-controlling interest in NMNLC | 124 | 1,792 |
Net increase (decrease) in net assets resulting from operations | $ 74,528 | $ 207,182 | 61,837
End of the period (in shares) | 100,937,026 | 97,907,441 |
End of the period | $ 1,326,191 | $ 1,342,612 | 1,236,889
Total Net Assets of NMFC |  |  |
Investment Company, Net Assets [Roll Forward] |  |  |
Beginning of the period | 1,321,245 | 1,221,875 | 1,283,468
Issuances of common stock | 41,104 | 14,655 |
Offering costs | (222) | (231) | 0
Distributions declared | (122,386) | (116,453) | (120,066)
Net increase (decrease) in net assets resulting from operations | 74,732 | 201,399 | 58,473
End of the period | $ 1,314,473 | $ 1,321,245 | $ 1,221,875
Common Stock |  |  |
Investment Company, Net Assets [Roll Forward] |  |  |
Beginning of the period (in shares) | 97,907,441 | 96,827,342 | 96,827,342
Beginning of the period | $ 979 | $ 968 | $ 968
Issuances of common stock (in shares) | 3,029,585 | 1,080,099 |
Issuances of common stock | $ 30 | $ 11 |
End of the period (in shares) | 100,937,026 | 97,907,441 | 96,827,342
End of the period | $ 1,009 | $ 979 | $ 968
Paid in Capital in Excess of Par |  |  |
Investment Company, Net Assets [Roll Forward] |  |  |
Beginning of the period | 1,272,796 | 1,269,671 | 1,287,853
Issuances of common stock | 41,074 | 14,644 |
Offering costs | (222) | (231) |
Tax reclassifications related to return of capital distributions (See Note 10) | (7,703) | (10,476) | (18,182)
Tax reclassifications related to return of capital distributions (See Note 10) |  | (11,288) |
End of the period | 1,305,945 | 1,272,796 | 1,269,671
Accumulated Net Investment Income |  |  |
Investment Company, Net Assets [Roll Forward] |  |  |
Beginning of the period | 118,330 | 105,981 | 91,333
Distributions declared | (122,386) | (116,453) | (120,066)
Net increase (decrease) in net assets resulting from operations | 118,497 | 117,514 | 116,532
Tax reclassifications related to return of capital distributions (See Note 10) | 33,152 | 10,476 | 18,182
Tax reclassifications related to return of capital distributions (See Note 10) |  | 11,288 |
End of the period | 147,593 | 118,330 | 105,981
Accumulated Net Realized (Losses) Gains |  |  |
Investment Company, Net Assets [Roll Forward] |  |  |
Beginning of the period | (92,099) | (88,250) | (85,448)
Net increase (decrease) in net assets resulting from operations | 49,476 | (3,849) | (2,802)
Tax reclassifications related to return of capital distributions (See Note 10) | (25,449) | 0 | 0
End of the period | (68,072) | (92,099) | (88,250)
Net Unrealized Appreciation (Depreciation) |  |  |
Investment Company, Net Assets [Roll Forward] |  |  |
Beginning of the period | 21,239 | (66,495) | (11,238)
Net increase (decrease) in net assets resulting from operations | (93,241) | 87,734 | (55,257)
End of the period | (72,002) | 21,239 | (66,495)
Non-Controlling Interest in NMNLC |  |  |
Investment Company, Net Assets [Roll Forward] |  |  |
Beginning of the period | 21,367 | 15,014 | 0
Distributions declared | (9,569) | (1,222) | (726)
Purchase of non-controlling interest in NMNLC |  |  | 12,376
Contributions related to non-controlling interest in NMNLC | 124 | 1,792 |
Net increase (decrease) in net assets resulting from operations | (204) | 5,783 | 3,364
End of the period | $ 11,718 | $ 21,367 | $ 15,014

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