CONDENSED FINANCIAL STATEMENTS OF PEAPACK-GLADSTONE FINANCIAL CORPORATION (PARENT COMPANY ONLY) (STATEMENTS OF CONDITION) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets
Cash	$ 4,415	$ 24,580
Interest-earning deposits	108,931	138,010
Total cash and cash equivalents	113,447	162,691	$ 70,160	$ 31,207
Securities available for sale	327,633	305,388
Other assets	26,926	13,876
Total assets	4,260,547	3,878,633	3,364,659
Liabilities
Subordinated debt	83,024	48,764
Other liabilities	28,521	22,334
Total liabilities	3,856,869	3,554,423
Shareholders' equity
Common stock	15,858	14,717
Surplus	283,552	238,708
Treasury stock	(8,988)	(8,988)
Retained earnings	114,468	81,304
Accumulated other comprehensive loss	(1,212)	(1,531)
Total shareholders' equity	403,678	324,210	$ 275,676	$ 242,267
Total liabilities and shareholders' equity	4,260,547	3,878,633
Parent Company [Member]
Assets
Cash	14,563	10,330
Interest-earning deposits	515	515
Total cash and cash equivalents	15,078	10,845
Investment in subsidiary	469,622	361,262
Other assets	2,551	1,303
Total assets	487,251	373,410
Liabilities
Subordinated debt	83,024	48,764
Other liabilities	549	436
Total liabilities	83,573	49,200
Shareholders' equity
Common stock	15,858	14,717
Surplus	283,552	238,708
Treasury stock	(8,988)	(8,988)
Retained earnings	114,253	81,304
Accumulated other comprehensive loss	(997)	(1,531)
Total shareholders' equity	403,678	324,210
Total liabilities and shareholders' equity	$ 487,251	$ 373,410