CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS EQUITY - USD ($)	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2018	$ 650,672,000	$ 10,438,000	$ 361,000	$ 546,849,000	$ 102,522,000	$ (9,498,000)
Beginning balance, shares at Dec. 31, 2018		10,438	36,343,239
Net income	12,597,000				12,597,000
Other comprehensive income (loss), net of tax	4,519,000					4,519,000
Issuance of common stock upon exercise of stock options	636,000		$ 1,000	635,000
Issuance of common stock upon exercise of stock options, shares			50,662
Restricted stock activity, shares			(8,500)
Issuance of common stock in connection with employee stock purchase plan	291,000			291,000
Issuance of common stock in connection with employee stock purchase plan, shares			12,743
Cumulative-effect adjustment (ASU 2016-01)					1,440,000	(1,440,000)
Cash dividends declared on preferred stock	(196,000)				(196,000)
Share-based compensation expense	230,000			230,000
Ending balance at Mar. 31, 2019	668,749,000	$ 10,438,000	$ 362,000	548,005,000	116,363,000	(6,419,000)
Ending balance, shares at Mar. 31, 2019		10,438	36,398,144
Beginning balance at Dec. 31, 2018	650,672,000	$ 10,438,000	$ 361,000	546,849,000	102,522,000	(9,498,000)
Beginning balance, shares at Dec. 31, 2018		10,438	36,343,239
Net income	41,150,000
Other comprehensive income (loss), net of tax	11,899,000
Cumulative-effect adjustment (ASU 2016-01)	(1,440,000)
Ending balance at Sep. 30, 2019	735,866,000	$ 10,438,000	$ 378,000	579,564,000	144,525,000	961,000
Ending balance, shares at Sep. 30, 2019		10,438	38,169,126
Beginning balance at Dec. 31, 2018	650,672,000	$ 10,438,000	$ 361,000	546,849,000	102,522,000	(9,498,000)
Beginning balance, shares at Dec. 31, 2018		10,438	36,343,239
Ending balance at Dec. 31, 2019	750,115,000	$ 10,438,000	$ 379,000	580,965,000	159,033,000	(700,000)
Ending balance, shares at Dec. 31, 2019		10,438	38,256,500
Beginning balance at Mar. 31, 2019	668,749,000	$ 10,438,000	$ 362,000	548,005,000	116,363,000	(6,419,000)
Beginning balance, shares at Mar. 31, 2019		10,438	36,398,144
Net income	13,211,000				13,211,000
Other comprehensive income (loss), net of tax	5,071,000					5,071,000
Issuance of common stock upon exercise of stock options	1,669,000		$ 1,000	1,668,000
Issuance of common stock upon exercise of stock options, shares			116,048
Issuance of common stock due to business combination,net of issuance costs	28,892,000		$ 15,000	28,877,000
Issuance of common stock due to business combination, net of issuance costs, shares			1,464,558
Restricted stock activity, shares			136,469
Cash dividends declared on preferred stock	(195,000)				(195,000)
Share-based compensation expense	278,000			278,000
Ending balance at Jun. 30, 2019	717,675,000	$ 10,438,000	$ 378,000	578,828,000	129,379,000	(1,348,000)
Ending balance, shares at Jun. 30, 2019		10,438	38,115,219
Net income	15,342,000				15,342,000
Other comprehensive income (loss), net of tax	2,309,000					2,309,000
Issuance of common stock upon exercise of stock options	54,000			54,000
Issuance of common stock upon exercise of stock options, shares			3,472
Issuance cost in connection with business combination	(157,000)			(157,000)
Restricted stock activity, shares			36,350
Issuance of common stock in connection with employee stock purchase plan	289,000			289,000
Issuance of common stock in connection with employee stock purchase plan, shares			14,085
Cash dividends declared on preferred stock	(196,000)				(196,000)
Cash dividends declared on common stock ($0.03 per share)	0
Share-based compensation expense	550,000			550,000
Ending balance at Sep. 30, 2019	735,866,000	$ 10,438,000	$ 378,000	579,564,000	144,525,000	961,000
Ending balance, shares at Sep. 30, 2019		10,438	38,169,126
Net income	15,852,000				15,852,000
Other comprehensive income (loss), net of tax	(1,661,000)					(1,661,000)
Issuance of common stock upon exercise of stock options	787,000			787,000
Issuance of common stock upon exercise of stock options, shares			71,029
Restricted stock activity			$ 1,000	(1,000)
Restricted stock activity, shares			16,345
Cash dividends declared on preferred stock	(196,000)				(196,000)
Cash dividends declared on common stock ($0.03 per share)	(1,148,000)				(1,148,000)
Share-based compensation expense	615,000			615,000
Ending balance at Dec. 31, 2019	750,115,000	$ 10,438,000	$ 379,000	580,965,000	159,033,000	(700,000)
Ending balance, shares at Dec. 31, 2019		10,438	38,256,500
Net income	2,966,000				2,966,000
Other comprehensive income (loss), net of tax	11,048,000					11,048,000
Issuance of common stock upon exercise of stock options	677,000		$ 1,000	676,000
Issuance of common stock upon exercise of stock options, shares			55,402
Restricted stock activity, shares			174,036
Issuance of common stock in connection with employee stock purchase plan	268,000			268,000
Issuance of common stock in connection with employee stock purchase plan, shares			15,569
Cash dividends declared on preferred stock	(196,000)				(196,000)
Cash dividends declared on common stock ($0.03 per share)	(1,151,000)				(1,151,000)
Repurchase of common stock	(1,668,000)						$ (1,668,000)
Repurchase of common stock, shares			(118,486)
Share-based compensation expense	608,000			608,000
Ending balance at Mar. 31, 2020	762,667,000	$ 10,438,000	$ 380,000	582,517,000	160,652,000	10,348,000	(1,668,000)
Ending balance, shares at Mar. 31, 2020		10,438	38,383,021
Beginning balance at Dec. 31, 2019	750,115,000	$ 10,438,000	$ 379,000	580,965,000	159,033,000	(700,000)
Beginning balance, shares at Dec. 31, 2019		10,438	38,256,500
Net income	25,176,000
Other comprehensive income (loss), net of tax	20,024,000
Ending balance at Sep. 30, 2020	794,696,000	$ 10,438,000	$ 383,000	586,057,000	180,162,000	19,324,000	(1,668,000)
Ending balance, shares at Sep. 30, 2020		10,438	38,568,916
Beginning balance at Mar. 31, 2020	762,667,000	$ 10,438,000	$ 380,000	582,517,000	160,652,000	10,348,000	(1,668,000)
Beginning balance, shares at Mar. 31, 2020		10,438	38,383,021
Net income	9,139,000				9,139,000
Other comprehensive income (loss), net of tax	9,685,000					9,685,000
Issuance of common stock upon exercise of stock options	56,000			56,000
Issuance of common stock upon exercise of stock options, shares			5,196
Restricted stock activity			$ 1,000	(1,000)
Cash dividends declared on preferred stock	(195,000)				(195,000)
Cash dividends declared on common stock ($0.03 per share)	(1,152,000)				(1,152,000)
Share-based compensation expense	735,000			735,000
Ending balance at Jun. 30, 2020	780,935,000	$ 10,438,000	$ 381,000	583,307,000	168,444,000	20,033,000	(1,668,000)
Ending balance, shares at Jun. 30, 2020		10,438	38,388,217
Net income	13,071,000				13,071,000
Other comprehensive income (loss), net of tax	(709,000)					(709,000)
Issuance of common stock upon exercise of stock options	1,815,000		$ 1,000	1,814,000
Issuance of common stock upon exercise of stock options, shares			165,375
Restricted stock activity, shares			(5,886)
Issuance of common stock in connection with employee stock purchase plan	269,000		$ 1,000	268,000
Issuance of common stock in connection with employee stock purchase plan, shares			21,210
Cash dividends declared on preferred stock	(196,000)				(196,000)
Cash dividends declared on common stock ($0.03 per share)	(1,157,000)				(1,157,000)
Share-based compensation expense	668,000			668,000
Ending balance at Sep. 30, 2020	$ 794,696,000	$ 10,438,000	$ 383,000	$ 586,057,000	$ 180,162,000	$ 19,324,000	$ (1,668,000)
Ending balance, shares at Sep. 30, 2020		10,438	38,568,916