v3.26.1
Cover - shares
 6 Months Ended
Jun. 30, 2026
Aug. 13, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Entity Interactive Data Current Yes  
Amendment Flag false  
Document Period End Date Jun. 30, 2026  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q2  
Entity Registrant Name NEWHOLD INVESTMENT CORP IV  
Entity Central Index Key 0002099767  
Entity Tax Identification Number 98-1888990  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Filer Category Non-accelerated Filer  
Entity File Number 001-43232  
Entity Shell Company true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Small Business true  
Entity Incorporation, State or Country Code E9  
Entity Address, Address Line One 110 West 40th St.  
Entity Address, Address Line Two Suite 802  
Entity Address, City or Town New York  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10018  
City Area Code (646)  
Local Phone Number 655-8504  
Units, each consisting of one Class A ordinary share, $0.0001 par value, and one-third of one redeemable warrant    
Document Information [Line Items]    
Trading Symbol NHIVU  
Title of 12(b) Security Units, each consisting of one Class A ordinary share, $0.0001 par value, and one-third of one redeemable warrant  
Security Exchange Name NASDAQ  
Class A ordinary shares included as part of the units    
Document Information [Line Items]    
Trading Symbol NHIV  
Title of 12(b) Security Class A ordinary shares included as part of the units  
Security Exchange Name NASDAQ  
Redeemable warrants included as part of the units, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50    
Document Information [Line Items]    
Trading Symbol NHIVW  
Title of 12(b) Security Redeemable warrants included as part of the units, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50  
Security Exchange Name NASDAQ  
Class A Ordinary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   20,766,250
Class B Ordinary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   6,708,333