CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Cash Flows [Abstract]
Net Cash Provided by (Used in) Operating Activities	$ 90,145	$ (59,961)
INVESTING ACTIVITIES
Purchases of securities	(89,038)	(30,292)
Proceeds from maturities, prepayments and calls of securities	34,715	33,869
Net proceeds from sales (purchases of) of Federal Home Loan Bank stock	831	(5,277)
Net decrease (increase) in loans	33,937	(122,507)
Proceeds from sale of loans not originated for resale	640	0
Purchases of premises and equipment	(811)	(1,429)
Proceeds from the sale of premises and equipment	74	0
Net Cash Used in Investing Activities	(19,652)	(125,636)
FINANCING ACTIVITIES
Net increase in core deposits	522,528	28,684
Net decrease in certificates of deposit	(67,003)	(7,042)
Net increase in securities sold under repurchase agreements	2,254	49,756
Net decrease (increase) in short-term borrowings	(75,000)	128,921
Repayments on long-term borrowings	(399)	(688)
Treasury shares issued-net	(135)	(563)
Cash dividends paid to common shareholders	(10,975)	(11,051)
Repurchase of common stock	0	(12,559)
Net Cash Provided by Financing Activities	371,270	175,458
Net increase (decrease) in cash and cash equivalents	441,763	(10,139)
Cash and cash equivalents at beginning of period	229,666	197,823
Cash and Cash Equivalents at End of Period	671,429	187,684
Supplemental Disclosures
Loans transferred to held for sale	2,798	0
Leased right-of-use operating assets and lease liabilities	0	91
Interest paid	5,368	17,795
Income taxes paid, net of refunds	197	210
Transfers of loans to other real estate owned	$ 77	$ 110