XML 69 R1.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Document and Entity Information Document - USD ($)
 12 Months Ended
Dec. 31, 2019
Feb. 20, 2020
Jun. 30, 2019
Cover page.      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2019    
Document Transition Report false    
Entity File Number 001-34762    
Entity Registrant Name FIRST FINANCIAL BANCORP.    
Entity Incorporation, State or Country Code OH    
Entity Tax Identification Number 31-1042001    
Entity address line two 255 East Fifth Street, Suite 800    
Entity Address, City or Town Cincinnati    
Entity Address, State or Province OH    
Entity Address, Postal Zip Code 45202    
City Area Code 877    
Local Phone Number 322-9530    
Title of 12(g) Security None    
Entity Well-known Seasoned Issuer Yes    
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     $ 2,341,389,000
Entity Common Stock, Shares Outstanding   98,490,998  
Entity Central Index Key 0000708955    
Current Fiscal Year End Date --12-31    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Amendment Flag false    
NASDAQ/NMS (GLOBAL MARKET) [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security Common stock, No par value    
Trading Symbol FFBC    
Security Exchange Name NASDAQ