CONSOLIDATED CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Preferred	Common Stock	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2018		125	49,349,800
Beginning balance at Dec. 31, 2018	$ 1,408,260	$ 125	$ 6,169	$ 840,052	$ 583,336	$ (21,422)
Comprehensive income:
Net income	116,630				116,630
Other comprehensive income (loss), net of tax	47,070					47,070
Cash dividends on common stock	(36,793)				(36,793)
Issuance of common stock related to acquisition (in shares)			6,383,806
Issuance of common stock related to acquisition	229,926		$ 798	229,128
Repurchase of common stock (in shares)			(516,016)
Repurchases of common stock	(19,041)		$ (65)	(18,976)
Share-based compensation (in shares)			113,043
Share-based compensation	2,887		$ 14	2,873
Stock issued under employee benefit plans (in shares)			16,117
Stock issued under employee benefit plans	518		$ 2	516
Stock issued under dividend reinvestment and stock purchase plan (in shares)			28,949
Stock issued under dividend reinvestment and stock purchase plan	1,109		$ 3	1,106
Stock options exercised (in shares)			12,950
Stock options exercised	121		$ 2	119
Stock redeemed (in shares)			(42,977)
Restricted shares withheld for taxes	(1,675)		$ (5)	(1,670)
Ending balance (in shares) at Sep. 30, 2019		125	55,345,672
Ending balance at Sep. 30, 2019	1,749,012	$ 125	$ 6,918	1,053,148	663,173	25,648
Beginning balance (in shares) at Jun. 30, 2019		125	49,456,594
Beginning balance at Jun. 30, 2019	1,501,636	$ 125	$ 6,182	841,365	639,362	14,602
Comprehensive income:
Net income	36,757				36,757
Other comprehensive income (loss), net of tax	11,046					11,046
Cash dividends on common stock	(12,946)				(12,946)
Issuance of common stock related to acquisition (in shares)			6,383,806
Issuance of common stock related to acquisition	229,926		$ 798	229,128
Repurchase of common stock (in shares)			(516,016)
Repurchases of common stock	(19,041)		$ (65)	(18,976)
Share-based compensation (in shares)			4,405
Share-based compensation	1,062		$ 0	1,062
Stock issued under employee benefit plans (in shares)			4,870
Stock issued under employee benefit plans	156		$ 1	155
Stock issued under dividend reinvestment and stock purchase plan (in shares)			10,263
Stock issued under dividend reinvestment and stock purchase plan	400		$ 1	399
Stock options exercised (in shares)			1,750
Stock options exercised	16		$ 1	15
Ending balance (in shares) at Sep. 30, 2019		125	55,345,672
Ending balance at Sep. 30, 2019	1,749,012	$ 125	$ 6,918	1,053,148	663,173	25,648
Beginning balance (in shares) at Dec. 31, 2019		125	55,368,482
Beginning balance at Dec. 31, 2019	1,786,437	$ 125	$ 6,921	1,054,997	696,520	27,874
Comprehensive income:
Net income	103,465				103,465
Other comprehensive income (loss), net of tax	37,594					37,594
Cash dividends on common stock	(42,435)				(42,435)
Repurchase of common stock (in shares)			(1,634,437)
Repurchases of common stock	(55,912)		$ (204)	(55,708)
Share-based compensation (in shares)			116,520
Share-based compensation	3,568		$ 15	3,553
Stock issued under employee benefit plans (in shares)			18,639
Stock issued under employee benefit plans	460		$ 2	458
Stock issued under dividend reinvestment and stock purchase plan (in shares)			49,148
Stock issued under dividend reinvestment and stock purchase plan	$ 1,293		$ 6	1,287
Stock options exercised (in shares)	10,050		10,050
Stock options exercised	$ 83		$ 1	82
Stock redeemed (in shares)			(36,669)
Restricted shares withheld for taxes	(897)		$ (5)	(892)
Ending balance (in shares) at Sep. 30, 2020		125	53,891,733
Ending balance at Sep. 30, 2020	1,833,656	$ 125	$ 6,736	1,003,777	757,550	65,468
Beginning balance (in shares) at Jun. 30, 2020		125	53,795,500
Beginning balance at Jun. 30, 2020	1,809,095	$ 125	$ 6,724	1,002,962	735,439	63,845
Comprehensive income:
Net income	36,210				36,210
Other comprehensive income (loss), net of tax	1,623					1,623
Cash dividends on common stock	(14,099)				(14,099)
Share-based compensation (in shares)			107,929
Share-based compensation	1,135		$ 14	1,121
Stock issued under employee benefit plans (in shares)			7,128
Stock issued under employee benefit plans	151		$ 1	150
Stock issued under dividend reinvestment and stock purchase plan (in shares)			17,541
Stock issued under dividend reinvestment and stock purchase plan	430		$ 2	428
Stock redeemed (in shares)			(36,365)
Restricted shares withheld for taxes	(889)		$ (5)	(884)
Ending balance (in shares) at Sep. 30, 2020		125	53,891,733
Ending balance at Sep. 30, 2020	$ 1,833,656	$ 125	$ 6,736	$ 1,003,777	$ 757,550	$ 65,468