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	103,465									103,465
Other comprehensive income, net of tax	37,594												37,594
Cash dividends on common stock ($.29 per share)	(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
Stock options exercised	83					$ 1		82
Restricted shares withheld for taxes (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, net of tax	1,623												1,623
Cash dividends on common stock ($.29 per share)	(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
Restricted shares withheld for taxes (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
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	157,798									157,798
Other comprehensive income, net of tax	(34,947)												(34,947)
Cash dividends on common stock ($.29 per share)	(45,608)									(45,608)
Repurchase of common stock (in shares)						(529,498)
Repurchases of common stock	(20,807)					$ (66)		(20,741)
Share-based compensation (in shares)						94,260
Share-based compensation	3,615					$ 12		3,603
Stock issued under employee benefit plans (in shares)						12,006
Stock issued under employee benefit plans	445					$ 2		443
Stock issued under dividend reinvestment and stock purchase plan (in shares)						32,322
Stock issued under dividend reinvestment and stock purchase plan	$ 1,405					$ 4		1,401
Stock options exercised (in shares)	17,300					17,300
Stock options exercised	$ 198					$ 2		196
Restricted shares withheld for taxes (in shares)						(38,004)
Restricted shares withheld for taxes	(1,614)					$ (5)		(1,609)
Ending balance (in shares) at Sep. 30, 2021				125		53,510,745
Ending balance at Sep. 30, 2021	1,868,090			$ 125		$ 6,689		988,659		832,728			39,889
Beginning balance (in shares) at Jun. 30, 2021				125		53,972,386
Beginning balance at Jun. 30, 2021	1,871,800			$ 125		$ 6,747		1,009,182		795,666			60,080
Comprehensive income:
Net income	52,770									52,770
Other comprehensive income, net of tax	(20,191)												(20,191)
Cash dividends on common stock ($.29 per share)	(15,708)									(15,708)
Repurchase of common stock (in shares)						(529,498)
Repurchases of common stock	(20,807)					$ (66)		(20,741)
Share-based compensation (in shares)						89,600
Share-based compensation	1,217					$ 11		1,206
Stock issued under employee benefit plans (in shares)						3,892
Stock issued under employee benefit plans	139					$ 1		138
Stock issued under dividend reinvestment and stock purchase plan (in shares)						12,102
Stock issued under dividend reinvestment and stock purchase plan	474					$ 1		473
Restricted shares withheld for taxes (in shares)						(37,737)
Restricted shares withheld for taxes	(1,604)					$ (5)		(1,599)
Ending balance (in shares) at Sep. 30, 2021				125		53,510,745
Ending balance at Sep. 30, 2021	$ 1,868,090			$ 125		$ 6,689		$ 988,659		$ 832,728			$ 39,889