Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating Activities:
Net income	$ 106,480	$ 84,941
Adjustments to reconcile net income to net cash from operating activities:
Provision for loan losses	6,945	7,952
Deferred tax expense (benefit)	10,411	(4,301)
Accretion of loan discounts	(3,378)	(3,913)
Securities premium amortization (discount accretion), net	24,260	21,638
Net (gain) loss on securities transactions	19	0
Depreciation and amortization	12,130	12,121
Net (gain) loss on sale/write-down of assets/foreclosed assets	(3,982)	(533)
Stock-based compensation	3,175	3,103
Net tax benefit from stock-based compensation	2,211	3,515
Earnings on life insurance policies	(820)	(783)
Net change in:
Trading account securities	1,326	(1,088)
Accrued interest receivable and other assets	23,555	55,705
Accrued interest payable and other liabilities	28,376	(48,702)
Net cash from operating activities	210,708	129,655
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	179,149	599,457
Securities available for sale:
Purchases	(3,245,923)	(466,004)
Sales	2,984,867	0
Maturities, calls and principal repayments	62,768	107,586
Proceeds from sale of loans	0	0
Net change in loans	(227,417)	(214,281)
Benefits received on life insurance policies	0	461
Proceeds from sales of premises and equipment	11,317	1,544
Purchases of premises and equipment	(16,759)	(6,311)
Proceeds from sales of repossessed properties	307	345
Net cash from investing activities	(253,191)	22,797
Financing Activities:
Net change in deposits	(194,611)	330,589
Net change in short-term borrowings	(115,603)	(81,792)
Proceeds from issuance of subordinated notes	0	98,446
Principal payments on subordinated notes	0	(100,000)
Proceeds from stock option exercises	19,165	24,747
Purchase of treasury stock	0	(42)
Cash dividends paid on preferred stock	(2,016)	(2,016)
Cash dividends paid on common stock	(36,551)	(34,656)
Net cash from financing activities	(329,616)	235,276
Net change in cash and cash equivalents	(372,099)	387,728
Cash and equivalents at beginning of period	5,053,047	4,141,445
Cash and equivalents at end of period	$ 4,680,948	$ 4,529,173