Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Activities:
Net income	$ 116,496	$ 106,480
Adjustments to reconcile net income to net cash from operating activities:
Provision for loan losses	11,003	6,945
Deferred tax expense (benefit)	(1,044)	10,411
Accretion of loan discounts	(3,757)	(3,378)
Securities premium amortization (discount accretion), net	28,696	24,260
Net (gain) loss on securities transactions	0	19
Depreciation and amortization	12,752	12,130
Net (gain) loss on sale/write-down of assets/foreclosed assets	(4,437)	(3,982)
Stock-based compensation	3,654	3,175
Net tax benefit from stock-based compensation	716	2,211
Earnings on life insurance policies	(898)	(820)
Net change in:
Trading account securities	1,582	1,326
Lease right-of-use assets	4,833	0
Accrued interest receivable and other assets	32,634	23,555
Accrued interest payable and other liabilities	(56,098)	28,376
Net cash from operating activities	146,132	210,708
Investing Activities:
Securities held-to-maturity - Purchases	0	(1,500)
Securities held to maturity: Maturities, calls and principal repayments	23,421	179,149
Securities available for sale:
Purchases	(1,526,279)	(3,245,923)
Sales	944,903	2,984,867
Maturities, calls and principal repayments	121,471	62,768
Proceeds from sale of loans	12,699	0
Net change in loans	(322,308)	(227,417)
Proceeds from sales of premises and equipment	4,667	11,317
Purchases of premises and equipment	(44,039)	(16,759)
Proceeds from sales of repossessed properties	0	307
Net cash from investing activities	(785,465)	(253,191)
Financing Activities:
Net change in deposits	(854,341)	(194,611)
Net change in short-term borrowings	(140,399)	(115,603)
Proceeds from stock option exercises	4,885	19,165
Purchase of treasury stock	(519)	0
Cash dividends paid on preferred stock	(2,016)	(2,016)
Cash dividends paid on common stock	(42,602)	(36,551)
Net cash from financing activities	(1,034,992)	(329,616)
Net change in cash and cash equivalents	(1,674,325)	(372,099)
Cash and equivalents at beginning of period	3,955,779	5,053,047
Cash and equivalents at end of period	$ 2,281,454	$ 4,680,948