Parent-Only Financial Information - Schedule of Condensed Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Financial Statements, Captions [Line Items]
Net (loss) gain on equity investments	$ (3,732)	$ 9,685	$ 7,145
Interest expense – borrowings	66,225	22,677	11,544
Operating expenses	248,912	234,881	226,860
Benefit for income taxes	(32,700)	(46,565)	(32,165)
Net income	104,065	147,357	110,076
Net income attributable to non-controlling interest	36	754	0
Net income attributable to OceanFirst Financial Corp.	104,029	146,603	110,076
OceanFirst Financial Corp.
Condensed Financial Statements, Captions [Line Items]
Dividend income – subsidiaries	97,043	73,011	40,000
Interest and dividend income – debt and equity securities	2,981	2,387	2,070
Interest income – advances to subsidiary Bank	2,182	562	298
Interest income – ESOP loan receivable	183	227	289
Net (loss) gain on equity investments	(3,732)	7,973	7,499
Total income	98,657	84,160	50,156
Interest expense – borrowings	13,569	10,861	11,102
Operating expenses	4,050	4,258	3,307
Income before income taxes and undistributed earnings of subsidiaries	81,038	69,041	35,747
Benefit for income taxes	3,807	959	1,018
Income before undistributed earnings of subsidiaries	84,845	70,000	36,765
Undistributed earnings of subsidiaries	19,220	77,357	73,311
Net income	104,065	147,357	110,076
Net income attributable to non-controlling interest	36	754	0
Net income attributable to OceanFirst Financial Corp.	$ 104,029	$ 146,603	$ 110,076