Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated Other Comprehensive Income (Loss), Net [Member]
Balance at Dec. 31, 2018	$ 3,081,340		$ 292,716	$ 1,725,741	$ 1,243,592		$ (180,709)
Balance, Shares Issued at Dec. 31, 2018			87,903
Net income (loss)	327,380				327,380
Other comprehensive income (loss)	125,985						125,985
Comprehensive income	453,365				327,380		125,985
Cash dividends declared	(94,871)				(94,871)
Common stock issued as consideration in business combination	193,849		$ 16,797	177,052
Common stock issued as consideration in business combination, Shares Issued			5,044
Common stock activity, long-term incentive plans	15,388			15,257	131
Issuance of stock from dividend reinvestment and stock purchase plans	3,614			3,614
Repurchase of common stock	(138,768)			(138,768)
Forward contract for accelerated share repurchase agreement	(46,232)			(46,232)
Balance at Dec. 31, 2019	3,467,685	$ (44,087)	$ 309,513	1,736,664	1,476,232	$ (44,087)	(54,724)
Balance, Shares Issued at Dec. 31, 2019			92,947
Net income (loss)	(45,174)				(45,174)
Other comprehensive income (loss)	134,793						134,793
Comprehensive income	89,619				(45,174)		134,793
Cash dividends declared	(95,605)				(95,605)
Common stock activity, long-term incentive plans	17,855			17,715	140
Issuance of stock from dividend reinvestment and stock purchase plans	4,164			4,164
Repurchase of common stock	(12,716)			(12,716)
Net settlement of accelerated share repurchase agreement (1,001,472 shares)	12,110			12,110
Balance at Dec. 31, 2020	$ 3,439,025		$ 309,513	1,757,937	1,291,506		80,069
Balance, Shares Issued at Dec. 31, 2020	92,947		92,947
Net income (loss)	$ 463,215				463,215
Other comprehensive income (loss)	(134,004)						(134,004)
Comprehensive income	329,211				463,215		(134,004)
Cash dividends declared	(95,927)				(95,927)
Common stock activity, long-term incentive plans	15,967			15,688	279
Issuance of stock from dividend reinvestment and stock purchase plans	3,872			3,872
Repurchase of common stock	(21,796)			(21,796)
Balance at Dec. 31, 2021	$ 3,670,352		$ 309,513	$ 1,755,701	$ 1,659,073		$ (53,935)
Balance, Shares Issued at Dec. 31, 2021	92,947		92,947