CONDENSED FINANCIAL STATEMENTS OF PEAPACK-GLADSTONE FINANCIAL CORPORATION (PARENT COMPANY ONLY) (STATEMENTS OF INCOME) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income
Other income													$ 34,627	$ 28,918	$ 23,714
Securities gains, net							$ 18	$ 101		$ 83	$ 176	$ 268		119	527
Expenses
Interest expenses	7,853	7,499	6,440	5,794	5,691	5,575	4,859	4,488	4,304	4,100	3,508	2,778	27,586	20,613	14,690
Other expenses													17,301	14,106	14,925
Total expenses	24,251	21,961	20,095	19,304	18,965	18,166	18,775	19,206	19,993	16,899	16,266	15,768
Loss before income tax benefit and equity in undistributed earnings of Bank	13,291	16,462	12,848	11,706	11,787	11,538	10,649	8,767	6,599	8,817	8,377	8,347	54,307	42,741	32,140
Income tax benefit	2,922	6,256	4,908	3,724	4,479	4,422	4,085	3,278	2,256	3,434	3,139	3,339	17,810	16,264	12,168
Net income	$ 10,369	$ 10,206	$ 7,940	$ 7,982	$ 7,308	$ 7,116	$ 6,564	$ 5,489	$ 4,343	$ 5,383	$ 5,238	$ 5,008	36,497	26,477	19,972
Other comprehensive income/(loss)													534	(1,152)	(1,600)
Comprehensive income													37,031	25,325	18,372
Parent Company [Member]
Income
Dividend from Bank
Other income													2	1	1
Total income													2	1	1
Expenses
Interest expenses													3,206	1,696
Other expenses													554	699	525
Total expenses													3,760	2,395	525
Loss before income tax benefit and equity in undistributed earnings of Bank													(3,758)	(2,394)	(524)
Income tax benefit													(1,313)	(835)	(180)
Net loss before equity in undistributed earnings of Bank													(2,445)	(1,559)	(344)
Equity in undistributed earnings of Bank/(dividends in excess of earnings)													38,942	28,036	20,316
Net income													36,497	26,477	19,972
Other comprehensive income/(loss)													534	(1,152)	(1,600)
Comprehensive income													$ 37,031	$ 25,325	$ 18,372