Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating Activities:
Net income	$ 228,082	$ 217,821
Adjustments to reconcile net income to net cash from operating activities:
Provision for loan losses	17,403	15,196
Deferred tax expense (benefit)	(675)	22,886
Accretion of loan discounts	(7,325)	(6,904)
Securities premium amortization (discount accretion), net	56,726	48,936
Net (gain) loss on securities transactions	(169)	79
Depreciation and amortization	25,705	24,581
Net (gain) loss on sale/write-down of assets/foreclosed assets	(5,135)	(5,453)
Stock-based compensation	8,018	6,760
Net tax benefit from stock-based compensation	1,131	3,160
Earnings on life insurance policies	(1,830)	(1,663)
Net change in:
Trading account securities	(1,068)	(2,263)
Lease right-of-use assets	9,167	0
Accrued interest receivable and other assets	(18,107)	(42,959)
Accrued interest payable and other liabilities	(20,008)	(26,176)
Net cash from operating activities	291,915	254,001
Investing Activities:
Securities held-to-maturity - Purchases	0	(1,500)
Securities held to maturity: Maturities, calls and principal repayments	60,077	183,140
Securities available for sale:
Purchases	(4,555,448)	(11,453,662)
Sales	3,291,529	10,890,388
Maturities, calls and principal repayments	708,273	108,316
Proceeds from sale of loans	24,036	18,918
Net change in loans	(390,452)	(601,101)
Benefits received on life insurance policies	0	384
Proceeds from sales of premises and equipment	4,677	12,844
Purchases of premises and equipment	(98,622)	(45,766)
Proceeds from sales of repossessed properties	5	986
Net cash from investing activities	(955,925)	(887,053)
Financing Activities:
Net change in deposits	(1,164,181)	(875,890)
Net change in short-term borrowings	(48,041)	(170,354)
Proceeds from stock option exercises	7,841	25,448
Purchase of treasury stock	(50,519)	(70)
Cash dividends paid on preferred stock	(4,031)	(4,031)
Cash dividends paid on common stock	(87,428)	(79,628)
Net cash from financing activities	(1,346,359)	(1,104,525)
Net change in cash and cash equivalents	(2,010,369)	(1,737,577)
Cash and equivalents at beginning of period	3,955,779	5,053,047
Cash and equivalents at end of period	$ 1,945,410	$ 3,315,470