Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ (111,033)	$ 79,164
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7,880	7,516
Provision for credit losses	246,793	18,043
(Gain) loss on other real estate and foreclosed assets	10,550	(991)
Gain on sale of securities	(112)
Deferred tax expense (benefit)	(34,279)	30,829
Increase in cash surrender value of life insurance contracts	(646)	(3,772)
Net (increase) decrease in loans held for sale	(5,709)	5,714
Net amortization of securities premium/discount	9,349	7,009
Amortization of intangible assets	5,345	5,138
Stock-based compensation expense	5,583	5,181
Net change in liability from variation margin collateral	(105,921)	(3,820)
Contribution to pension plan		(100,000)
Decrease in interest payable and other liabilities	(18,641)	(11,658)
(Increase) decrease in other assets	9,887	(23,335)
Other, net	(7,521)	(1,595)
Net cash provided by operating activities	11,525	13,423
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from the sale of available for sale securities	124,122
Proceeds from maturities of securities available for sale	166,265	55,596
Purchases of securities available for sale	(367,944)	(1,502)
Proceeds from maturities of securities held to maturity	84,176	79,533
Net increase in short-term investments	(766,085)	(52,668)
Proceeds from sales of loans and leases	2,608	42,059
Net increase in loans	(339,888)	(148,073)
Purchases of property and equipment	(9,460)	(12,435)
Proceeds from sales of other real estate	3,007	4,613
Final cash settlement for acquisition of business		(1,112)
Other, net	(1,731)	(8,863)
Net cash used in investing activities	(1,104,930)	(42,852)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in deposits	1,204,921	230,109
Net decrease in short-term borrowings	(41,589)	(200,393)
Repayments of long-term debt	(76)	(75)
Dividends paid	(24,028)	(23,581)
Payroll tax remitted on net share settlement of equity awards	(1,494)	(688)
Proceeds from dividend reinvestment and stock purchase plans	984	879
Settlement of forward contract portion of accelerated share repurchase	12,110
Repurchase of shares	(12,716)
Net cash provided by financing activities	1,138,112	6,251
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	44,707	(23,178)
CASH AND DUE FROM BANKS, BEGINNING	432,104	383,372
CASH AND DUE FROM BANKS, ENDING	476,811	360,194
SUPPLEMENTAL INFORMATION FOR NON-CASH INVESTING AND FINANCING ACTIVITIES
Assets acquired in settlement of loans	$ 1,612	$ 4,273