Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Pascack Bancorp, Inc.	Harmony Bank	Common Stock	Common Stock Pascack Bancorp, Inc.	Common Stock Harmony Bank	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period at Dec. 31, 2014	$ 379,438			$ 384,731			$ (6,816)	$ 1,523
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	32,481						32,481
Other comprehensive income (loss), net of tax	(373)							(373)
Stock based compensation	1,605			1,605
Issuance of stock	22			22
Retirement of restricted stock	(254)			(254)
Exercise of stock options, net of excess tax benefits	183			183
Cash dividends, common stock	(12,586)						(12,586)
Balance at end of period at Dec. 31, 2015	400,516			386,287			13,079	1,150
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	41,518						41,518
Other comprehensive income (loss), net of tax	(557)							(557)
Stock based compensation	1,899			1,899
Common stock issued for acquisitions		$ 37,221	$ 36,654		$ 37,221	$ 36,654
Issuance of stock	48,678			48,678
Retirement of restricted stock	(206)			(206)
Exercise of stock options, net of excess tax benefits	328			328
Cash dividends, common stock	(16,007)						(16,007)
Balance at end of period at Dec. 31, 2016	550,044			510,861			38,590	593
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	52,580						52,580
Other comprehensive income (loss), net of tax	(2,522)							(2,522)
Adjustment related to implementation of ASU 2018-02							420	(420)
Stock based compensation	2,325			2,325
Retirement of restricted stock	(773)			(773)
Exercise of stock options, net of excess tax benefits	321			321
Cash dividends, common stock	(18,853)						(18,853)
Balance at end of period at Dec. 31, 2017	$ 583,122			$ 512,734			$ 72,737	$ (2,349)