Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash Flows from Operating Activities
Interest and dividends received	$ 615,078,000	$ 512,693,000	$ 410,155,000
Service charges and other fees received	43,694,000	43,859,000	37,782,000
Interest paid	(95,505,000)	(8,583,000)	(6,010,000)
Net cash paid to vendors, employees and others	(197,739,000)	(185,300,000)	(176,807,000)
Income taxes	(69,896,000)	(88,938,000)	(69,878,000)
Net cash provided by operating activities	295,632,000	273,731,000	195,242,000
Cash Flows from Investing Activities
Proceeds of FHLB stock, net	9,615,000	(4,903,000)	0
Net change in interest-earning balances from depository institutions	1,337,000	26,446,000	17,564,000
Proceeds from repayment of investment securities available-for-sale	374,490,000	423,040,000	775,538,000
Proceeds from maturity of investment securities available-for-sale	329,000	90,172,000	330,000
Purchases of investment securities available-for-sale	(46,415,000)	(1,146,071,000)	(1,648,575,000)
Proceeds from repayment and maturity of investment securities held-to-maturity	75,457,000	148,239,000	152,575,000
Purchases of investment securities held-to-maturity	(2,026,000)	(659,039,000)	(1,510,112,000)
Net (increase) decrease in equity investments	(13,594,000)	1,980,000	(4,010,000)
Net decrease (increase) in loan and lease finance receivables	180,332,000	(400,217,000)	497,293,000
Proceeds from sale of building, net of selling costs	0	8,315,000	1,157,000
Purchase of premises and equipment	(4,521,000)	(5,359,000)	(4,677,000)
Proceeds from redemption of BOLI policies	67,768,000	0	0
Purchase of BOLI policies	(109,000,000)	0	(25,000,000)
Proceeds from BOLI death benefit	2,505,000	11,430,000	12,414,000
Proceeds from sales of other real estate owned	0	0	5,012,000
Cash acquired from acquisition, net of cash paid	0	329,001,000	0
Net cash provided by (used in) investing activities	536,276,000	(1,176,966,000)	(1,730,491,000)
Cash Flows from Financing Activities
Net (decrease) increase in other deposits	(1,504,372,000)	(1,219,107,000)	1,313,953,000
Net increase (decrease) in time deposits	101,769,000	(103,661,000)	(74,012,000)
Net increase (decrease) in other borrowings	1,075,000,000	992,719,000	(2,719,000)
Net (decrease) increase in customer repurchase agreements	(293,789,000)	(76,957,000)	202,982,000
Repayment of junior subordinated debentures	0	0	(25,774,000)
Cash dividends on common stock	(111,686,000)	(104,439,000)	(97,733,000)
Repurchase of common stock	(21,216,000)	(46,330,000)	(8,337,000)
Repurchase of common stock, ASR Plan	0	(70,000,000)	0
Proceeds from exercise of stock options	210,000	1,923,000	1,277,000
Net cash (used in) provided by financing activities	(754,084,000)	(625,852,000)	1,309,637,000
Net increase (decrease) in cash and cash equivalents	77,824,000	(1,529,087,000)	(225,612,000)
Cash and cash equivalents, beginning of period	203,461,000	1,732,548,000	1,958,160,000
Cash and cash equivalents, end of period	281,285,000	203,461,000	1,732,548,000
Reconciliation of Net Earnings to Net Cash Provided by Operating Activities
Net earnings	221,435,000	235,425,000	212,521,000
Adjustments to reconcile net earnings to net cash provided by operating activities:
Gain on sale of building, net	0	(2,717,000)	(189,000)
Gain on sale of other real estate owned	0	0	(1,177,000)
Write-down of BOLI	(4,465,000)	0	0
Increase in BOLI	(8,286,000)	(5,356,000)	(8,500,000)
Net amortization of premiums and discounts on investment securities	18,049,000	26,565,000	32,232,000
Accretion of discount for acquired loans, net	(3,886,000)	(7,904,000)	(12,270,000)
Provision for (recapture of) credit loss	2,000,000	10,600,000	(25,500,000)
(Recapture of) provision for unfunded loan commitments	(500,000)	0	(1,000,000)
Stock-based compensation	9,439,000	7,901,000	5,183,000
Depreciation and amortization, net	18,169,000	13,661,000	(6,426,000)
Change in other assets and liabilities	43,677,000	(4,444,000)	368,000
Total adjustments	74,197,000	38,306,000	(17,279,000)
Net cash provided by operating activities	295,632,000	273,731,000	195,242,000
Supplemental Disclosure of Non-cash Investing Activities
Securities matured and not settled	15,000,000	0	0
Securities purchased and not settled	0	0	50,340,000
Transfer of loans to other real estate owned	0	0	443,000
Issuance of common stock for acquisition	$ 0	$ 197,069,000	$ 0