Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 123,478	$ 107,172
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7,177	7,083
Provision for credit losses	(22,527)	(4,911)
Gain on other real estate and foreclosed assets	(3,014)	(253)
Loss on sale of securities	87
Deferred tax expense	10,099	2,300
Increase in cash surrender value of life insurance contracts	(634)	(9,400)
Net decrease in loans held for sale	27,250	8,031
Net amortization of securities premium/discount	11,356	13,211
Amortization of intangible assets	3,748	4,419
Stock-based compensation expense	5,292	5,517
Net change in liability from variation margin collateral	15,828	56,744
Increase (decrease) in interest payable and other liabilities	18,512	(23,472)
Decrease in other assets	91,643	98,052
Other, net	(7,761)	(9,453)
Net cash provided by operating activities	280,534	255,040
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from the sale of available for sale securities	73,219
Proceeds from maturities of securities available for sale	167,949	311,232
Purchases of securities available for sale	(228,454)	(1,164,798)
Proceeds from maturities of securities held to maturity	28,125	37,830
Purchases of securities held to maturity	(391,761)	(59,362)
Net decrease in short-term borrowings	697,625	(1,005,325)
Proceeds from sales of loans and leases	18,890	7,373
Net (increase) decrease in loans	(227,948)	101,924
Purchase of life insurance contracts	(60,000)	(45,000)
Proceeds from the surrender of life insurance contracts		44,045
Purchases of property and equipment	(11,353)	(4,269)
Proceeds from sales of other real estate	6,227	4,191
Other, net	3,002	5,809
Net cash provided by (used in) investing activities	75,521	(1,766,350)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in deposits	33,812	1,512,643
Net decrease in short-term borrowings	(44,759)	(14,766)
Proceeds from the issuance of long-term debt		22,388
Repayments of long-term debt	(79)	(3,209)
Dividends paid	(23,804)	(24,021)
Payroll tax remitted on net share settlement of equity awards	(1,396)	(494)
Proceeds from exercise of stock options		132
Proceeds from dividend reinvestment and stock purchase plans	881	1,004
Repurchase of shares	(18,490)
Net cash provided by (used in) financing activities	(53,835)	1,493,677
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	302,220	(17,633)
CASH AND DUE FROM BANKS, BEGINNING	401,201	526,306
CASH AND DUE FROM BANKS, ENDING	703,421	508,673
SUPPLEMENTAL INFORMATION FOR NON-CASH INVESTING AND FINANCING ACTIVITIES
Assets acquired in settlement of loans	$ 118	$ 1,799