Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	$ 88,847	$ 78,007
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	11,500	4,041
Depreciation and amortization of premises and equipment	13,974	13,804
Net amortization of investment securities premiums	4,775	4,647
Investment securities gains, net	(2,542)	(1,023)
Gain on sales of mortgage loans held for sale	(6,562)	(7,110)
Proceeds from sales of mortgage loans held for sale	283,251	304,516
Originations of mortgage loans held for sale	(281,356)	(314,850)
Amortization of issuance costs on long-term debt	382	193
Stock-based compensation	1,769	3,256
Excess tax benefits from stock-based compensation	0	(28)
Increase in accrued interest receivable	(1,309)	(549)
Increase in other assets	(26,610)	(18,268)
Decrease in accrued interest payable	(1,828)	(2,388)
(Decrease) increase in other liabilities	(9,327)	9,866
Total adjustments	(13,883)	(3,893)
Net cash provided by operating activities	74,964	74,114
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales of securities available for sale	29,518	84,972
Proceeds from principal repayments and maturities of securities available for sale	225,788	282,832
Purchase of securities available for sale	(158,078)	(355,220)
Increase in short-term investments	(101,590)	(115,570)
Net increase in loans	(655,172)	(326,902)
Net purchases of premises and equipment	(13,726)	(17,130)
Net cash used in investing activities	(673,260)	(447,018)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in demand and savings deposits	351,329	202,552
Net decrease in time deposits	(6,832)	(42,305)
Increase in short-term borrowings	153,542	224,551
Additions to long-term debt	223,251	16,000
Repayments of long-term debt	(115,075)	(183)
Net proceeds from issuance of common stock	4,870	3,320
Excess tax benefits from stock-based compensation	0	28
Dividends paid	(36,614)	(31,278)
Acquisition of treasury stock	0	(16,254)
Net cash provided by financing activities	574,471	356,431
Net Decrease in Cash and Due From Banks	(23,825)	(16,473)
Cash and Due From Banks at Beginning of Period	118,763	101,120
Cash and Due From Banks at End of Period	94,938	84,647
Cash paid during the period for:
Interest	45,054	43,038
Income taxes	7,016	9,087
Supplemental schedule of certain noncash activities:
Transfer of student loans to loans held for sale	$ 28,990	$ 0