Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Cumulative Effect, Period of Adoption, Adjustment [Member] Common Stock Outstanding [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Additional Paid-in Capital [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] AOCI Attributable to Parent [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Treasury Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock Outstanding [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Total
Balance (in shares) at Dec. 31, 2020							79,508,265
Beginning balance, loss, net of tax (Accounting Standards Update 2016-13 [Member]) at Dec. 31, 2020	$ 0	$ 0	$ 0	$ (3,139)	$ 0	$ (3,139)
Beginning balance, loss, net of tax at Dec. 31, 2020							$ 906	$ 964,734	$ 5,310	$ 1,789,325	$ (342,131)	$ 2,418,144
Dividend Reinvestment Plan (in shares)							40,059
Dividend Reinvestment Plan							$ 1	1,724	0	0	0	1,725
Restricted stock units vested (in shares)							121,922
Restricted stock units vested							$ 1	0	0	0	0	1
Stock issued to directors							0	850	0	0	0	850
Shares withheld related to net share settlement of RSUs							$ 0	(2,594)	0	0	0	(2,594)
Purchases of treasury stock (in shares)							(1,532,406)
Purchases of treasury stock							$ 0	0	0	0	(63,529)	(63,529)
Stock-based compensation							0	2,452	0	0	0	2,452
Cash dividends							0	0	0	(49,198)	0	(49,198)
Other comprehensive income (loss)							0	0	(2,938)	0	0	(2,938)
Net income							$ 0	0	0	150,583	0	150,583
Balance (in shares) at Jun. 30, 2021							78,158,590
Ending balance, loss, net of tax at Jun. 30, 2021							$ 908	967,166	2,372	1,887,571	(405,660)	2,452,357
Balance (in shares) at Mar. 31, 2021							79,595,025
Beginning balance, loss, net of tax at Mar. 31, 2021							$ 907	965,566	1,686	1,834,920	(342,131)	2,460,948
Dividend Reinvestment Plan (in shares)							20,023
Dividend Reinvestment Plan							$ 1	856	0	0	0	857
Restricted stock units vested (in shares)							55,198
Restricted stock units vested							$ 0	0	0	0	0	0
Stock issued to directors (in shares)							20,750
Stock issued to directors							$ 0	850	0	0	0	850
Shares withheld related to net share settlement of RSUs							$ 0	(1,315)	0	0	0	(1,315)
Purchases of treasury stock (in shares)							(1,532,406)
Purchases of treasury stock							$ 0	0	0	0	(63,529)	(63,529)
Stock-based compensation							0	1,209	0	0	0	1,209
Cash dividends							0	0	0	(24,548)	0	(24,548)
Other comprehensive income (loss)							0	0	686	0	0	686
Net income							$ 0	0	0	77,199	0	77,199
Balance (in shares) at Jun. 30, 2021							78,158,590
Ending balance, loss, net of tax at Jun. 30, 2021							$ 908	967,166	2,372	1,887,571	(405,660)	2,452,357
Balance (in shares) at Dec. 31, 2021							75,750,862
Beginning balance, loss, net of tax at Dec. 31, 2021							$ 909	972,474	(3,065)	1,985,168	(509,235)	2,446,251
Dividend Reinvestment Plan (in shares)							43,262
Dividend Reinvestment Plan							$ 0	1,872	0	0	0	1,872
Restricted stock units vested (in shares)							62,905
Restricted stock units vested							$ 1	0	0	0	0	1
Stock issued to directors (in shares)							19,780
Stock issued to directors							$ 0	849	0	0	0	849
Shares withheld related to net share settlement of RSUs							$ 0	(2,015)	0	0	0	(2,015)
Purchases of treasury stock (in shares)							(1,454,925)
Purchases of treasury stock							$ 0	0	0	0	(63,484)	(63,484)
Stock-based compensation							0	3,367	0	0	0	3,367
Cash dividends							0	0	0	(51,052)	0	(51,052)
Other comprehensive income (loss)							0	0	(68,263)	0	0	(68,263)
Net income							$ 0	0	0	164,006	0	164,006
Balance (in shares) at Jun. 30, 2022							74,421,884
Ending balance, loss, net of tax at Jun. 30, 2022							$ 910	976,547	(71,328)	2,098,122	(572,719)	2,431,532
Balance (in shares) at Mar. 31, 2022							75,078,258
Beginning balance, loss, net of tax at Mar. 31, 2022							$ 909	974,748	(45,977)	2,034,681	(542,131)	2,422,230
Dividend Reinvestment Plan (in shares)							21,847
Dividend Reinvestment Plan							$ 0	927	0	0	0	927
Restricted stock units vested (in shares)							51,997
Restricted stock units vested							$ 1	0	0	0	0	1
Stock issued to directors (in shares)							19,780
Stock issued to directors							$ 0	849	0	0	0	849
Shares withheld related to net share settlement of RSUs							$ 0	(1,730)	0	0	0	$ (1,730)
Purchases of treasury stock (in shares)							(749,998)					(749,998)
Purchases of treasury stock							$ 0	0	0	0	(30,588)	$ (30,588)
Stock-based compensation							0	1,753	0	0	0	1,753
Cash dividends							0	0	0	(25,537)	0	(25,537)
Other comprehensive income (loss)							0	0	(25,351)	0	0	(25,351)
Net income							$ 0	0	0	88,978	0	88,978
Balance (in shares) at Jun. 30, 2022							74,421,884
Ending balance, loss, net of tax at Jun. 30, 2022							$ 910	$ 976,547	$ (71,328)	$ 2,098,122	$ (572,719)	$ 2,431,532