CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss)	Total
Balance at Dec. 31, 2017		$ 412,546	$ 13,602	$ 160,025	$ (16,717)	$ (4,019)	$ 565,437
Reclassification of stranded tax effects (ASU 2018-02) (see Note 16)				709		(709)
Cumulative effect of adopting ASU 2016-01 (see Note 16)				(55)		55
Net income				60,352			60,352
Other comprehensive income (loss), net of tax						(4,116)	(4,116)
Cash dividends declared on common stock				(9,686)			(9,686)
Exercise of stock options			875				875
Net shares issued in satisfaction of performance units earned			(819)				(819)
Stock-based compensation expense			1,884				1,884
Balance at Dec. 31, 2018		412,546	15,542	211,345	(16,717)	(8,789)	613,927
Net income				73,395			73,395
Other comprehensive income (loss), net of tax						7,642	7,642
Cash dividends declared on common stock				(12,958)			(12,958)
Repurchase of stock					(12,643)		(12,643)
Exercise of stock options			360				360
Net shares issued in satisfaction of performance units earned			196				196
Stock issued in acquisition of GHB		56,025					56,025
Stock issued in acquisition of BoeFly, LLC			2,500				2,500
Stock-based compensation expense			2,746				2,746
Balance at Dec. 31, 2019		468,571	21,344	271,782	(29,360)	(1,147)	731,190
Net income				71,289			71,289
Other comprehensive income (loss), net of tax						3,944	3,944
Cash dividends declared on common stock				(11,120)			(11,120)
Repurchase of treasury stock					(911)		(911)
Exercise of stock options			233				233
Net shares issued in satisfaction of performance units earned
Share redemption for tax withholdings on performance units and restricted stock units earned			(639)				(639)
Stock issued in acquisition of Bancorp of New Jersey		118,375					118,375
Stock-based compensation expense			2,949				2,949
Balance at Dec. 31, 2020		$ 586,946	$ 23,887	$ 331,951	$ (30,271)	$ 2,797	$ 915,310