CONDENSED FINANCIAL STATEMENTS OF PEAPACK-GLADSTONE FINANCIAL CORPORATION (PARENT COMPANY ONLY) (STATEMENTS OF CASH FLOWS) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities:
Net income	$ 44,170	$ 36,497	$ 26,477
Amortization of subordinated debt costs	169	135	71
Increase in other assets	(8,485)	(9,977)	945
(Decrease)/increase in accrued expenses and other liabilities	(929)	2,330	2,935
Net cash provided by operating activities	64,248	55,935	42,926
Investing activities:
Net cash used in investing activities	(297,707)	(435,514)	(433,175)
Financing activities:
Cash dividends paid on common stock	(3,712)	(3,548)	(3,296)
Exercise of stock options, net stock swaps	275	690	1,069
Proceeds from issuance of subordinated debt		34,125	48,693
Issuance of common shares (DRIP program)	16,677	36,588	22,461
Net cash provided by financing activities	280,785	330,335	482,780
Net increase/(decrease) in cash and cash equivalents	47,326	(49,244)	92,531
Parent Company [Member]
Operating activities:
Net income	44,170	36,497	26,477
Undistributed earnings of Bank	(48,410)	(38,942)	(28,036)
Amortization of subordinated debt costs	171	135	71
Increase in other assets	(1,183)	(1,248)	(889)
(Decrease)/increase in accrued expenses and other liabilities	(256)	113	114
Net cash provided by operating activities	(5,508)	(3,445)	(2,263)
Investing activities:
Capital contribution to subsidiary	(9,322)	(60,177)	(57,823)
Net cash used in investing activities	(9,322)	(60,177)	(57,823)
Financing activities:
Cash dividends paid on common stock	(3,712)	(3,548)	(3,296)
Exercise of stock options, net stock swaps	275	690	1,069
Proceeds from issuance of subordinated debt		34,125	48,693
Issuance of common shares (DRIP program)	16,677	36,588	22,461
Net cash provided by financing activities	13,240	67,855	68,927
Net increase/(decrease) in cash and cash equivalents	(1,590)	4,233	8,841
Cash and cash equivalents at beginning of period	15,078	10,845	2,004
Cash and cash equivalents at end of period	$ 13,488	$ 15,078	$ 10,845