Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating Activities:
Net income	$ 54,753	$ 116,496
Adjustments to reconcile net income to net cash from operating activities:
Credit loss expense	175,197	11,003
Deferred tax expense (benefit)	(26,089)	(1,044)
Accretion of loan discounts	(4,060)	(3,757)
Securities premium amortization (discount accretion), net	31,760	28,696
Net (gain) loss on securities transactions	(108,989)	0
Depreciation and amortization	15,518	12,752
Net (gain) loss on sale/write-down of assets/foreclosed assets	397	(4,437)
Stock-based compensation	2,512	3,654
Net tax benefit from stock-based compensation	336	716
Earnings on life insurance policies	(922)	(898)
Net change in:
Trading account securities	(12,819)	1,582
Lease right-of-use assets	5,620	4,833
Accrued interest receivable and other assets	(81,100)	32,634
Accrued interest payable and other liabilities	196,814	(56,098)
Net cash from operating activities	248,928	146,132
Investing Activities:
Securities held-to-maturity - Purchases	(1,500)	0
Securities held to maturity: Maturities, calls and principal repayments	41,526	23,421
Securities available for sale:
Purchases	(687,759)	(1,526,279)
Sales	1,111,102	944,903
Maturities, calls and principal repayments	581,882	121,471
Proceeds from sale of loans	0	12,699
Net change in loans	(622,514)	(322,308)
Benefits received on life insurance policies	0	0
Proceeds from sales of premises and equipment	1	4,667
Purchases of premises and equipment	(31,749)	(44,039)
Proceeds from sales of repossessed properties	8	0
Net cash from investing activities	390,997	(785,465)
Financing Activities:
Net change in deposits	501,303	(854,341)
Net change in short-term borrowings	(524,364)	(140,399)
Redemption of preferred stock	(150,000)	0
Proceeds from stock option exercises	1,463	4,885
Purchase of treasury stock	(13,973)	(519)
Cash dividends paid on preferred stock	(2,016)	(2,016)
Cash dividends paid on common stock	(44,934)	(42,602)
Net cash from financing activities	(232,521)	(1,034,992)
Net change in cash and cash equivalents	407,404	(1,674,325)
Cash and cash equivalents at beginning of period	3,788,181	3,955,779
Cash and cash equivalents at end of period	$ 4,195,585	$ 2,281,454