Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating Activities:
Net income	$ 217,821	$ 170,494
Adjustments to reconcile net income to net cash from operating activities:
Provision for loan losses	15,196	16,378
Deferred tax expense (benefit)	22,886	(4,173)
Accretion of loan discounts	(6,904)	(7,403)
Securities premium amortization (discount accretion), net	48,936	43,652
Net (gain) loss on securities transactions	79	50
Depreciation and amortization	24,581	24,055
Net (gain) loss on sale/write-down of assets/foreclosed assets	(5,453)	(1,383)
Stock-based compensation	6,760	6,291
Net tax benefit from stock-based compensation	3,160	5,579
Earnings on life insurance policies	(1,663)	(1,565)
Net change in:
Trading account securities	(2,263)	(7,120)
Accrued interest receivable and other assets	(42,959)	(20,116)
Accrued interest payable and other liabilities	(26,176)	(36,277)
Net cash from operating activities	254,001	188,462
Investing Activities:
Securities held-to-maturity - Purchases	(1,500)	0
Securities held-to-maturity - Sales	0	0
Securities held to maturity: Maturities, calls and principal repayments	183,140	634,874
Securities available for sale:
Purchases	(11,453,662)	(8,825,545)
Sales	10,890,388	8,247,439
Maturities, calls and principal repayments	108,316	164,182
Proceeds from sale of loans	18,918	0
Net change in loans	(601,101)	(549,408)
Benefits received on life insurance policies	384	462
Proceeds from sales of premises and equipment	12,844	1,550
Purchases of premises and equipment	(45,766)	(14,481)
Proceeds from sales of repossessed properties	986	345
Net cash from investing activities	(887,053)	(340,582)
Financing Activities:
Net change in deposits	(875,890)	(198,002)
Net change in short-term borrowings	(170,354)	(52,125)
Proceeds from issuance of subordinated notes	0	98,434
Principal payments on subordinated notes	0	(100,000)
Proceeds from stock option exercises	25,448	44,149
Purchase of treasury stock	(70)	(42)
Cash dividends paid on preferred stock	(4,031)	(4,031)
Cash dividends paid on common stock	(79,628)	(71,393)
Net cash from financing activities	(1,104,525)	(283,010)
Net change in cash and cash equivalents	(1,737,577)	(435,130)
Cash and equivalents at beginning of period	5,053,047	4,141,445
Cash and equivalents at end of period	$ 3,315,470	$ 3,706,315