CONSOLIDATED CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Cumulative effect of ASC 326 adoption	Adjusted balance	Preferred	Preferred Adjusted balance	Common Stock	Common Stock Adjusted balance	Additional Paid in Capital	Additional Paid in Capital Adjusted balance	Retained Earnings	Retained Earnings Cumulative effect of ASC 326 adoption	Retained Earnings Adjusted balance	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Adjusted balance
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	67,255									67,255
Other comprehensive income, net of tax	35,971												35,971
Cash dividends on common stock	(28,336)									(28,336)
Repurchase of common stock (in shares)						(1,634,437)
Repurchases of common stock	(55,912)					$ (204)		(55,708)
Share-based compensation (in shares)						8,591
Share-based compensation	2,433					$ 1		2,432
Stock issued under employee benefit plans (in shares)						11,511
Stock issued under employee benefit plans	309					$ 1		308
Stock issued under dividend reinvestment and stock purchase plan (in shares)						31,607
Stock issued under dividend reinvestment and stock purchase plan	863					$ 4		859
Stock options exercised (in shares)						10,050
Stock options exercised	83					$ 1		82
Restricted shares withheld for taxes (in shares)						(304)
Restricted shares withheld for taxes	(8)							(8)
Ending balance (in shares) at Jun. 30, 2020				125		53,795,500
Ending balance at Jun. 30, 2020	1,809,095			$ 125		$ 6,724		1,002,962		735,439			63,845
Beginning balance (in shares) at Mar. 31, 2020				125		53,754,137
Beginning balance at Mar. 31, 2020	1,777,960			$ 125		$ 6,719		1,000,942		716,518			53,656
Comprehensive income:
Net income	32,992									32,992
Other comprehensive income, net of tax	10,189												10,189
Cash dividends on common stock	(14,071)									(14,071)
Share-based compensation (in shares)						5,259
Share-based compensation	1,213					$ 1		1,212
Stock issued under employee benefit plans (in shares)						11,511
Stock issued under employee benefit plans	309					$ 1		308
Stock issued under dividend reinvestment and stock purchase plan (in shares)						15,897
Stock issued under dividend reinvestment and stock purchase plan	435					$ 2		433
Stock options exercised (in shares)						9,000
Stock options exercised	76					$ 1		75
Restricted shares withheld for taxes (in shares)						(304)
Restricted shares withheld for taxes	(8)							(8)
Ending balance (in shares) at Jun. 30, 2020				125		53,795,500
Ending balance at Jun. 30, 2020	1,809,095			$ 125		$ 6,724		1,002,962		735,439			63,845
Beginning balance (in shares) at Dec. 31, 2020				125	125	53,922,359	53,922,359
Beginning balance at Dec. 31, 2020	1,875,645	$ (68,040)	$ 1,807,605	$ 125	$ 125	$ 6,740	$ 6,740	1,005,366	$ 1,005,366	788,578	$ (68,040)	$ 720,538	74,836	$ 74,836
Comprehensive income:
Net income	105,028									105,028
Other comprehensive income, net of tax	(14,756)												(14,756)
Cash dividends on common stock	(29,900)									(29,900)
Share-based compensation (in shares)						4,660
Share-based compensation	2,398					$ 1		2,397
Stock issued under employee benefit plans (in shares)						8,114
Stock issued under employee benefit plans	306					$ 1		305
Stock issued under dividend reinvestment and stock purchase plan (in shares)						20,220
Stock issued under dividend reinvestment and stock purchase plan	$ 931					$ 3		928
Stock options exercised (in shares)	17,300					17,300
Stock options exercised	$ 198					$ 2		196
Restricted shares withheld for taxes (in shares)						(267)
Restricted shares withheld for taxes	(10)							(10)
Ending balance (in shares) at Jun. 30, 2021				125		53,972,386
Ending balance at Jun. 30, 2021	1,871,800			$ 125		$ 6,747		1,009,182		795,666			60,080
Beginning balance (in shares) at Mar. 31, 2021				125			53,953,723
Beginning balance at Mar. 31, 2021			$ 1,805,856		$ 125		$ 6,744		$ 1,007,300			$ 755,877		$ 35,810
Comprehensive income:
Net income	55,559									55,559
Other comprehensive income, net of tax	24,270												24,270
Cash dividends on common stock	(15,770)									(15,770)
Share-based compensation (in shares)						375
Share-based compensation	1,208							1,208
Stock issued under employee benefit plans (in shares)						4,185
Stock issued under employee benefit plans	162					$ 1		161
Stock issued under dividend reinvestment and stock purchase plan (in shares)						11,103
Stock issued under dividend reinvestment and stock purchase plan	488					$ 2		486
Stock options exercised (in shares)						3,000
Stock options exercised	27							27
Ending balance (in shares) at Jun. 30, 2021				125		53,972,386
Ending balance at Jun. 30, 2021	$ 1,871,800			$ 125		$ 6,747		$ 1,009,182		$ 795,666			$ 60,080