Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Beginning Period Balance at Dec. 31, 2020	$ 3,594,951	$ 1,207	$ 3,100,633	$ 409,391	$ (88,803)	$ 172,523
Shares outstanding, beginning balance (shares) at Dec. 31, 2020		118,414,853
Stockholders' Equity Disclosure [Rollforward]
Net earnings	150,406			150,406
Other comprehensive income - net unrealized gain on securities available-for-sale, net of tax	(66,142)					(66,142)
Restricted stock awarded and earned compensation, net of shares forfeited (shares)		743,444
Restricted stock awarded and earned stock compensation, net of shares forfeited	6,417	$ 8	6,409
Restricted stock surrendered (shares)		(52,655)
Restricted stock surrendered	(1,908)				(1,908)
Cash dividends paid	(29,587)		(29,587)
Ending Period Balance at Mar. 31, 2021	$ 3,654,137	$ 1,215	3,077,455	559,797	(90,711)	106,381
Shares outstanding, ending balance (shares) at Mar. 31, 2021		119,105,642
Dividends declared per share (usd per share)	$ 0.25
Beginning Period Balance at Dec. 31, 2021	$ 3,999,630	$ 1,221	3,013,399	1,016,350	(97,308)	65,968
Shares outstanding, beginning balance (shares) at Dec. 31, 2021		119,584,854
Stockholders' Equity Disclosure [Rollforward]
Net earnings	120,128			120,128
Other comprehensive income - net unrealized gain on securities available-for-sale, net of tax	(442,443)					(442,443)
Restricted stock awarded and earned compensation, net of shares forfeited (shares)		109,466
Restricted stock awarded and earned stock compensation, net of shares forfeited	7,557	$ 1	7,556
Restricted stock surrendered (shares)		(92,554)
Restricted stock surrendered	(4,481)				(4,481)
Cash dividends paid	(29,796)		(29,796)
Ending Period Balance at Mar. 31, 2022	$ 3,650,595	$ 1,222	$ 2,991,159	$ 1,136,478	$ (101,789)	$ (376,475)
Shares outstanding, ending balance (shares) at Mar. 31, 2022		119,601,766