XML 12 R1.htm IDEA: XBRL DOCUMENT v3.22.0.1
Document and Entity Information - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2021
Mar. 07, 2022
Jun. 30, 2021
Document And Entity Information (Abstract)      
Document Type 10-K    
Document Annual Report true    
Document Transition Report false    
Document Period End Date Dec. 31, 2021    
Entity Registrant Name METROPOLITAN BANK HOLDING CORP.    
Entity File Number 001-38282    
Entity Incorporation, State or Country Code NY    
Entity Tax Identification Number 13-4042724    
Entity Address, Address Line One 99 Park Avenue    
Entity Address, City or Town New York    
Entity Address, State or Province NY    
Entity Address, Postal Zip Code 10016    
City Area Code 212    
Local Phone Number 659-0600    
Title of 12(b) Security Common Stock, $0.01 par value    
Trading Symbol MCB    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company true    
Entity Ex Transition Period false    
ICFR Auditor Attestation Flag false    
Entity Shell Company false    
Entity Public Float     $ 475.0
Entity Common Stock, Shares Outstanding   10,931,697  
Entity Central Index Key 0001476034    
Current Fiscal Year End Date --12-31    
Document Fiscal Year Focus 2021    
Document Fiscal Period Focus FY    
Amendment Flag false    
Auditor Name Crowe LLP    
Auditor Firm ID 173    
Auditor Location New York, New York