CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total	Impact of CECL Adoption	[1]	Common Stock	Additional  Paid-in Capital	Accumulated Retained Earnings	Accumulated Retained Earnings Impact of CECL Adoption	[1]	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2017		$ 1,241,996			$ 458	$ 1,063,974	$ 177,149			$ 415
Beginning balance (in shares) at Dec. 31, 2017					46,245,050
Increase (Decrease) in Stockholders' Equity
Net income		123,340					123,340
Other comprehensive income (loss)		(6,098)								(6,098)
Share-based compensation expense		9,033				9,033
Issuance of restricted stock, net		0
Issuance of restricted stock, net (in shares)					270,571
Issuance of common stock		601,171			$ 158	601,013
Issuance of common stock (in shares)					15,758,039
Restricted stock surrendered and canceled		(1,669)				(1,669)
Restricted stock surrendered and canceled (in shares)					(33,148)
Exercise of stock options, net		1,924			$ 1	1,923
Exercise of stock options, net (in shares)					240,243
Reclassification of certain tax effects of the Tax Cuts and Jobs Act		0					(82)			82
Ending balance at Dec. 31, 2018		1,969,697			$ 617	1,674,274	300,407			(5,601)
Ending balance (in shares) at Dec. 31, 2018					62,480,755
Increase (Decrease) in Stockholders' Equity
Net income		159,718					159,718
Other comprehensive income (loss)		27,124								27,124
Repurchase and retirement of common stock		(100,000)			$ (33)	(89,887)	(10,080)
Repurchase and retirement of common stock (in shares)					(3,364,761)
Cash dividends declared		(53,867)					(53,867)
Dividend equivalents declared		0				127	(127)
Share-based compensation expense		10,528				10,528
Issuance of restricted stock, net		0
Issuance of restricted stock, net (in shares)					316,754
Restricted stock surrendered and canceled		(3,285)				(3,285)
Restricted stock surrendered and canceled (in shares)					(139,569)
Exercise of stock options, net		$ 2,679			$ 2	2,677
Exercise of stock options, net (in shares)					212,878
Accounting standards update [Extensible List]	[1]	us-gaap:AccountingStandardsUpdate201613Member
Ending balance at Dec. 31, 2019		$ 2,012,594	$ (45,625)		$ 586	1,594,434	396,051	$ (45,625)		21,523
Ending balance (in shares) at Dec. 31, 2019		59,506,057			59,506,057
Increase (Decrease) in Stockholders' Equity
Net income		$ 60,351					60,351
Other comprehensive income (loss)		38,769								38,769
Cash dividends declared		(79,901)					(79,901)
Dividend equivalents declared		0				321	(321)
Share-based compensation expense		10,859				10,859
Issuance of restricted stock, net		0
Issuance of restricted stock, net (in shares)					563,330
Issuance of common stock - acquisition		749,603			$ 344	749,259
Issuance of common stock - acquisition (in shares)					34,407,403
Restricted stock surrendered and canceled		(1,653)				(1,653)
Restricted stock surrendered and canceled (in shares)					(116,439)
Exercise of stock options, net		1,652			$ 1	1,651
Exercise of stock options, net (in shares)					122,785
Ending balance at Dec. 31, 2020		$ 2,746,649			$ 931	$ 2,354,871	$ 330,555			$ 60,292
Ending balance (in shares) at Dec. 31, 2020		94,483,136			94,483,136

[1] Related to the adoption of Accounting Standards Update 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. See Note 1 - Description of Business and Summary of Significant Accounting Policies.