Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	$ 171,753	$ 161,625	$ 149,502
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	23,305	13,182	2,250
Depreciation and amortization of premises and equipment	28,096	27,403	27,605
Net amortization of investment security premiums	10,107	10,430	7,330
Deferred income tax expense	24,896	11,054	13,424
Re-measurement of net deferred tax asset	15,635	0	0
Investment securities gains, net	(9,071)	(2,550)	(9,066)
Gains on sales of mortgage loans held for sale	(13,036)	(15,685)	(13,264)
Proceeds from sales of mortgage loans held for sale	644,400	709,316	757,850
Originations of mortgage loans held for sale	(634,197)	(705,442)	(743,950)
Intangible amortization	0	0	247
Amortization of financing costs	845	617	582
Stock-based compensation	5,209	6,556	5,938
Excess tax benefits from stock-based compensation	0	(964)	(201)
Increase in accrued interest receivable	(6,616)	(3,527)	(949)
Loss on redemption of trust preferred securities	0	0	5,626
Decrease (increase) in other assets	29,227	(29,940)	(22,987)
Decrease in accrued interest payable	(315)	(1,092)	(7,321)
(Decrease) increase in other liabilities	(31,412)	4,427	4,928
Total adjustments	87,073	23,785	28,042
Net cash provided by operating activities	258,826	185,410	177,544
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales of securities available for sale	184,734	115,844	66,480
Proceeds from maturities and paydowns of securities available for sale	417,673	558,854	439,533
Purchase of securities available for sale	(584,921)	(782,765)	(683,839)
(Increase) decrease in short-term investments	(63,314)	1,264	130,567
Net increase in loans	(1,087,521)	(873,939)	(743,655)
Net purchases of premises and equipment	(33,092)	(19,674)	(27,113)
Net cash used in investing activities	(1,166,441)	(1,000,416)	(818,027)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in demand and savings deposits	782,525	992,253	971,312
Net increase (decrease) in time deposits	2,143	(111,706)	(206,501)
Increase in short-term borrowings	76,207	43,654	167,944
Additions to long-term debt	223,251	215,884	347,778
Repayments of long-term debt	(115,153)	(236,640)	(540,079)
Net proceeds from issuance of common stock	8,538	16,167	10,607
Excess tax benefits from stock-based compensation	0	964	201
Dividends paid	(80,368)	(69,382)	(65,361)
Acquisition of treasury stock	0	(18,545)	(50,000)
Net cash provided by financing activities	897,143	832,649	635,901
Net (decrease) increase in Cash and Due From Banks	(10,472)	17,643	(4,582)
Cash and Due From Banks at Beginning of Year	118,763	101,120	105,702
Cash and Due From Banks at End of Year	108,291	118,763	101,120
Cash paid during period for:
Interest	93,817	83,420	91,116
Income taxes	$ 6,537	$ 16,193	$ 13,378