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, 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
Issuance of stock for acquisition		$ 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)
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)
Adjustment related to implementation of ASU 2018-02							420	(420)
Balance at end of period at Dec. 31, 2017	583,122			512,734			72,737	(2,349)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative adjustment for adoption							2,000	(420)
Net income	63,401						63,401
Other comprehensive income (loss), net of tax	(3,446)							(3,446)
Stock based compensation	2,425			2,425
Retirement of restricted stock	(763)			(763)
Exercise of stock options, net of excess tax benefits	307			307
Cash dividends, common stock	(21,307)						(21,307)
Balance at end of period at Dec. 31, 2018	$ 623,739			$ 514,703			$ 116,874	$ (7,838)