XML 24 R1.htm IDEA: XBRL DOCUMENT v3.20.1
Cover Page - USD ($)
 12 Months Ended
Dec. 31, 2019
Mar. 13, 2020
Jun. 30, 2019
Cover page.      
Document Type 10-K/A    
Document Annual Report true    
Document Period End Date Dec. 31, 2019    
Document Transition Report false    
Entity File Number 001-35791    
Entity Registrant Name Northfield Bancorp, Inc.    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 80-0882592    
Entity Address, Address Line One 581 Main Street,    
Entity Address, City or Town Woodbridge,    
Entity Address, State or Province NJ    
Entity Address, Postal Zip Code 07095    
City Area Code 732    
Local Phone Number 499-7200    
Title of 12(b) Security Common Stock, par value $0.01 per share    
Trading Symbol NFBK    
Security Exchange Name NASDAQ    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 669,416,040
Entity Common Stock, Shares Outstanding   49,188,347  
Documents Incorporated by Reference
None
    
Amendment Flag true    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Entity Central Index Key 0001493225    
Current Fiscal Year End Date --12-31