Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock Outstanding [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Treasury Stock, Common [Member]	Total
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 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
Stock issued to directors						900
Shares withheld related to net share settlement of RSUs						(3,500)
Purchases of treasury stock						(16,700)
Cash dividends						(49,300)
Net income						189,200
Balance (in shares) at Jun. 30, 2023	72,563,169
Ending balance, loss, net of tax at Jun. 30, 2023	$ 913	983,233	(99,049)	2,384,817	(667,243)	2,602,671
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)
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
Balance (in shares) at Dec. 31, 2022	72,742,151
Beginning balance, loss, net of tax at Dec. 31, 2022	$ 911	981,119	(102,295)	2,244,856	(650,551)	2,474,040
Dividend Reinvestment Plan (in shares)	49,872
Dividend Reinvestment Plan	$ 1	1,833	0	0	0	1,834
Restricted stock units vested (in shares)	120,876
Restricted stock units vested	$ 1	0	0	0	0	1
Stock issued to directors (in shares)	25,360
Stock issued to directors	$ 0	850	0	0	0	850
Shares withheld related to net share settlement of RSUs	$ 0	(3,527)	0	0	0	(3,527)
Purchases of treasury stock (in shares)	(375,090)
Purchases of treasury stock	$ 0	0	0	0	(16,692)	(16,692)
Stock-based compensation	0	2,958	0	0	0	2,958
Cash dividends	0	0	0	(49,266)	0	(49,266)
Other comprehensive income/(loss)	0	0	3,246	0	0	3,246
Net income	$ 0	0	0	189,227	0	189,227
Balance (in shares) at Jun. 30, 2023	72,563,169
Ending balance, loss, net of tax at Jun. 30, 2023	$ 913	983,233	(99,049)	2,384,817	(667,243)	2,602,671
Balance (in shares) at Mar. 31, 2023	72,390,694
Beginning balance, loss, net of tax at Mar. 31, 2023	$ 911	983,534	(91,077)	2,316,258	(667,287)	2,542,339
Dividend Reinvestment Plan (in shares)	26,852
Dividend Reinvestment Plan	$ 1	915	0	0	0	916
Restricted stock units vested (in shares)	120,263
Restricted stock units vested	$ 1	0	0	0	0	1
Stock issued to directors (in shares)	25,360
Stock issued to directors	$ 0	849	0	0	0	849
Shares withheld related to net share settlement of RSUs	$ 0	(3,512)	0	0	0	(3,512)
Purchases of treasury stock (in shares)	0
Purchases of treasury stock	$ 0	0	0	0	(44)	(44)
Stock-based compensation	0	1,447	0	0	0	1,447
Cash dividends	0	0	0	(24,661)	0	(24,661)
Other comprehensive income/(loss)	0	0	(7,972)	0	0	(7,972)
Net income	$ 0	0	0	93,220	0	93,220
Balance (in shares) at Jun. 30, 2023	72,563,169
Ending balance, loss, net of tax at Jun. 30, 2023	$ 913	$ 983,233	$ (99,049)	$ 2,384,817	$ (667,243)	$ 2,602,671