Cover Page - shares	3 Months Ended
	Mar. 31, 2020	May 04, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Transition Report	false
Entity File Number	001-11713
Entity Registrant Name	OceanFirst Financial Corp
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	22-3412577
Entity Address, Address Line One	110 West Front Street,
Entity Address, City or Town	Red Bank,
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	07701
City Area Code	732
Local Phone Number	240-4500
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 Common Stock, Shares Outstanding		60,577,925
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001004702
Current Fiscal Year End Date	--12-31
Common stock, $0.01 par value per share
Entity Information [Line Items]
Title of 12(b) Security	Common stock, $0.01 par value per share
Trading Symbol	OCFC
Security Exchange Name	NASDAQ
Depositary Shares (each representing a 1/40th interest in a share of 7.0% Series A Non-Cumulative, perpetual preferred stock)
Entity Information [Line Items]
Title of 12(b) Security	Depositary Shares (each representing a 1/40th interest in a share of 7.0% Series A Non-Cumulative, perpetual preferred stock)
Trading Symbol	OCFCP
Security Exchange Name	NASDAQ