BUSINESS SEGMENTS - Schedule of Income and Total Assets for Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Net interest income	$ 33,845	$ 31,971	$ 65,638	$ 63,718
Noninterest income	17,678	12,626	35,498	27,143
Total income	51,523	44,597	101,136	90,861
Provision for loan and lease losses	900	4,900	1,125	24,900
Compensation and benefits	19,910	19,186	41,900	38,412
Premises and equipment expense	4,074	4,036	8,187	8,079
FDIC expense	529	455	1,114	705
Other operating expense	6,171	5,337	11,077	10,053
Total operating expense	31,584	33,914	63,403	82,149
Income before income tax (benefit)/expense	19,939	10,683	37,733	8,712
Income tax expense/(benefit)	5,521	2,441	10,137	(903)
NET INCOME	14,418	8,242	27,596	9,615
Total assets at period end	5,791,688	6,281,215	5,791,688	6,281,215	$ 5,890,442
Banking [Member]
Net interest income	32,399	30,453	62,625	60,862
Noninterest income	4,194	2,356	9,334	6,585
Total income	36,593	32,809	71,959	67,447
Provision for loan and lease losses	900	4,900	1,125	24,900
Compensation and benefits	14,369	13,774	30,797	26,981
Premises and equipment expense	3,519	3,487	7,089	6,908
FDIC expense	529	455	1,114	705
Other operating expense	3,817	3,052	6,208	5,658
Total operating expense	23,134	25,668	46,333	65,152
Income before income tax (benefit)/expense	13,459	7,141	25,626	2,295
Income tax expense/(benefit)	3,721	1,257	6,880	(2,636)
NET INCOME	9,738	5,884	18,746	4,931
Total assets at period end	5,700,105	6,203,441	5,700,105	6,203,441
Peapack Private [Member]
Net interest income	1,446	1,518	3,013	2,856
Noninterest income	13,484	10,270	26,164	20,558
Total income	14,930	11,788	29,177	23,414
Provision for loan and lease losses	0	0	0	0
Compensation and benefits	5,541	5,412	11,103	11,431
Premises and equipment expense	555	549	1,098	1,171
FDIC expense	0	0	0	0
Other operating expense	2,354	2,285	4,869	4,395
Total operating expense	8,450	8,246	17,070	16,997
Income before income tax (benefit)/expense	6,480	3,542	12,107	6,417
Income tax expense/(benefit)	1,800	1,184	3,257	1,733
NET INCOME	4,680	2,358	8,850	4,684
Total assets at period end	$ 91,583	$ 77,774	$ 91,583	$ 77,774