Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
OPERATING ACTIVITIES
Net income	$ 243,519	$ 180,055
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	6,900	16,500
Net amortization of premiums and discounts from acquisition	736	251
Depreciation and amortization	26,194	27,714
Amortization of debt issuance costs	225	225
Deferred income tax expense	584	825
Net decrease (increase) in trading securities and other earning assets	22,229	(19,006)
Gains on investment securities, net	(60,198)	(7,119)
Gains on sales of assets	(3,184)	(3,358)
Amortization of securities premiums, net of discount accretion	22,964	29,373
Originations of loans held for sale	(21,131)	(83,962)
Gains on sales of loans held for sale, net	(609)	(3,242)
Proceeds from sales of loans held for sale	22,267	88,609
Equity-based compensation	11,902	9,304
Net tax benefit related to equity compensation plans	2,313	1,743
Changes in:
Accrued income	(13,871)	4,501
Accrued expenses and taxes	(68,434)	(61,192)
Other assets and liabilities, net	213,403	(3,964)
Net cash provided by operating activities	405,809	177,257
Securities held to maturity:
Maturities, calls and principal repayments	223,317	110,262
Purchases	(851,840)	(179,657)
Securities available for sale:
Sales	0	176,802
Maturities, calls and principal repayments	725,027	957,564
Purchases	(1,151,486)	(2,322,572)
Equity securities with readily determinable fair values:
Sales	17,081	72,801
Purchases	(700)	(508)
Equity securities without readily determinable fair values:
Sales	13	2,499
Maturities, calls and principal repayments	83
Purchases	(16,232)	(11,928)
Payment on low-income housing tax credit investment commitments	(22,096)	(5,695)
Net increase in loans	(1,889,693)	(846,915)
Net decrease in fed funds sold and resell agreements	160,898	503,814
Net cash activity from acquisitions and divestitures	257,767	18,431
Net decrease (increase) in interest-bearing balances due from other financial institutions	38,596	(29,066)
Purchases of premises and equipment	(16,889)	(15,391)
Proceeds from sales of premises and equipment	6,644	1,828
Purchases of bank-owned and company-owned life insurance		(100,000)
Net cash used in investing activities	(2,519,510)	(1,667,731)
FINANCING ACTIVITIES
Net (decrease) increase in demand and savings deposits	(4,042,398)	3,195,002
Net decrease in time deposits	(298,259)	(197,782)
Net (decrease) increase in fed funds purchased and repurchase agreements	(577,152)	467,892
Cash dividends paid	(35,790)	(30,935)
Proceeds from exercise of stock options and sales of treasury shares	1,029	14,425
Purchases of treasury stock	(31,806)	(4,088)
Net cash (used in) provided by financing activities	(4,984,376)	3,444,514
(Decrease) increase in cash and cash equivalents	(7,098,077)	1,954,040
Cash and cash equivalents at beginning of period	9,214,564	3,497,566
Cash and cash equivalents at end of period	2,116,487	5,451,606
Supplemental disclosures:
Income tax payments	54,785	48,003
Total interest payments	31,239	24,388
Noncash disclosures:
Acquisition of low-income housing tax credit investments	27,490	12,622
Commitment to fund low-income housing tax credit investments	27,490	$ 12,622
Transfer of loans to other real estate owned	12,313
Transfer of securities from available-for-sale to held-to-maturity	$ 3,593,711