Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2024	Jul. 31, 2024
Document And Entity Information (Abstract)
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2024
Document Transition Report	false
Entity File Number	001-38282
Entity Registrant Name	Metropolitan Bank Holding Corp.
Entity Incorporation, State or Country Code	NY
Entity Tax Identification Number	13-4042724
Entity Address, Postal Zip Code	10016
Entity Address, Address Line One	99 Park Avenue
Entity Address, City or Town	New York
Entity Address, State or Province	NY
City Area Code	212
Local Phone Number	659-0600
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	MCB
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		11,192,936
Entity Central Index Key	0001476034
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Amendment Flag	false