Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	$ 43,380	$ 38,257
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	4,800	1,530
Depreciation and amortization of premises and equipment	7,032	6,949
Net amortization of investment securities premiums	2,416	2,055
Investment securities gains, net	(1,106)	(947)
Gain on sales of mortgage loans held for sale	(3,074)	(2,670)
Proceeds from sales of mortgage loans held for sale	115,417	114,255
Originations of mortgage loans held for sale	(108,429)	(114,418)
Amortization of issuance costs on long-term debt	168	154
Stock-based compensation	734	1,436
Excess tax benefits from stock-based compensation	0	(10)
Increase in accrued interest receivable	(61)	(1,612)
Decreases (increase) in other assets	4,614	(4,469)
Increase in accrued interest payable	2,874	2,843
Decrease in other liabilities	(4,244)	(9,245)
Total adjustments	21,141	(4,149)
Net cash provided by operating activities	64,521	34,108
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales of securities available for sale	8,735	46,541
Proceeds from principal repayments and maturities of securities available for sale	98,024	117,221
Purchase of securities available for sale	(49,430)	(169,436)
Increase in short-term investments	(59,135)	(115,544)
Net increase in loans	(267,383)	(38,976)
Net purchases of premises and equipment	(5,397)	(9,471)
Net cash used in investing activities	(274,586)	(169,665)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in demand and savings deposits	112,348	269,899
Net (decrease) increase in time deposits	(34,868)	2,064
Decrease in short-term borrowings	(88,000)	(144,780)
Additions to long-term debt	223,375	16,000
Repayments of long-term debt	(15,037)	(42)
Net proceeds from issuance of common stock	4,731	1,637
Excess tax benefits from stock-based compensation	0	10
Dividends paid	(17,403)	(15,676)
Acquisition of treasury stock	0	(11,196)
Net cash provided by financing activities	185,146	117,916
Net Decrease in Cash and Due From Banks	(24,919)	(17,641)
Cash and Due From Banks at Beginning of Period	118,763	101,120
Cash and Due From Banks at End of Period	93,844	83,479
Cash paid during the period for:
Interest	18,034	17,414
Income taxes	$ 116	$ 3,972