Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Employee Stock Ownership Plan	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Common Stock Acquired by Deferred Compensation Plan	Deferred Compensation Plan Liability	Sun Bancorp, Inc.	Sun Bancorp, Inc. Common Stock	Sun Bancorp, Inc. Additional Paid-In Capital	Sun Bancorp, Inc. Treasury Stock	Capital Bank of New Jersey	Capital Bank of New Jersey Common Stock	Capital Bank of New Jersey Additional Paid-In Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Effect of adopting Accounting Standards Update (ASU) | Accounting Standards Update 2016-01	$ 0					$ (147)	$ 147
Beginning Balance at Dec. 31, 2017	601,941	$ (2,479)	$ 0	$ 336	$ 354,377	271,023	(5,349)	$ (15,967)	$ (84)	$ 84
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	45,200					45,200
Other comprehensive income, net of tax	1,259						1,259
Stock awards	2,530			2	2,528
Acquisition of common stock by ESOP	(8,400)	(8,400)
Allocation of ESOP stock	1,249	767			482
Cash dividend per share	(21,425)					(21,425)
Exercise of stock options	4,936			4	12,919	(8,189)		202
Sale (purchase) of stock for the deferred compensation plan	0								(3)	3
Acquisition, value											$ 402,554	$ 141	$ 386,648	$ 15,765
Ending Balance at Sep. 30, 2018	1,029,844	(10,112)	0	483	756,954	286,462	(3,943)	0	(87)	87
Beginning Balance at Jun. 30, 2018	1,012,568	(10,232)	0	482	752,223	273,749	(3,654)	0	(84)	84
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	24,071					24,071
Other comprehensive income, net of tax	(289)						(289)
Stock awards	743			0	743
Allocation of ESOP stock	283	120			163
Cash dividend per share	(7,151)					(7,151)
Exercise of stock options	(381)			1	3,825	(4,207)
Sale (purchase) of stock for the deferred compensation plan	0
Ending Balance at Sep. 30, 2018	1,029,844	(10,112)	0	483	756,954	286,462	(3,943)	0	(87)	87
Beginning Balance at Dec. 31, 2018	1,039,358	(9,857)	0	483	757,963	305,056	(3,450)	(10,837)	(87)	87
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	65,124					65,124
Other comprehensive income, net of tax	2,095						2,095
Stock awards	3,140			2	3,138
Allocation of ESOP stock	1,182	907			275
Cash dividend per share	(25,943)					(25,943)
Exercise of stock options	1,145			2	1,751	(608)		0
Purchase of shares of common stock	(18,054)							(18,054)
Sale (purchase) of stock for the deferred compensation plan	0								(4)	4
Acquisition, value															$ 76,481	$ 32	$ 76,449
Ending Balance at Sep. 30, 2019	1,144,528	(8,950)	0	519	839,576	343,629	(1,355)	(28,891)	(91)	91
Beginning Balance at Jun. 30, 2019	1,137,295	(9,252)	0	518	838,610	327,297	(1,643)	(18,235)	(90)	90
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	24,971					24,971
Other comprehensive income, net of tax	288						288
Stock awards	538				538
Allocation of ESOP stock	381	302			79
Cash dividend per share	(8,639)					(8,639)
Exercise of stock options	350			1	349
Purchase of shares of common stock	(10,656)							(10,656)
Sale (purchase) of stock for the deferred compensation plan	0								(1)	1
Ending Balance at Sep. 30, 2019	$ 1,144,528	$ (8,950)	$ 0	$ 519	$ 839,576	$ 343,629	$ (1,355)	$ (28,891)	$ (91)	$ 91