Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2024	Aug. 06, 2024
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	814-00646
Entity Registrant Name	MIDCAP FINANCIAL INVESTMENT CORPORATION
Entity Central Index Key	0001278752
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	52-2439556
Entity Address, Address Line One	9 West 57th Street37th Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10019
City Area Code	212
Local Phone Number	515-3450
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		93,780,278
Common Stock
Document Information [Line Items]
Security 12b Title	Common Stock, $0.001 par value
Trading Symbol	MFIC
Security Exchange Name	NASDAQ
8.00% Notes Due 2028
Document Information [Line Items]
Security 12b Title	8.00% Notes due 2028
Trading Symbol	MFICL
Security Exchange Name	NASDAQ