Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	$ 65,140,000	$ 59,469,000
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	11,497,000	10,729,000
Provision for loan losses	1,650,000	2,075,000
Deferred income tax expense	443,000	314,000
Net (gain) loss on sale of securities	(13,000)	27,000
Net (gain) loss on bank premises and equipment	(93,000)	10,000
Loss on extinguishment of debt	0	437,000
Net loss on other real estate owned and foreclosed assets	308,000	41,000
Realized gain on sale leaseback transaction	(775,000)	(775,000)
Stock based compensation	2,346,000	2,308,000
Excess tax benefit related to equity award activity	0	(354,000)
Increase in cash surrender value of life insurance policies	(3,000,000)	(2,980,000)
Net change in:
Trading assets	(494,000)	(453,000)
Loans held for sale	578,000	(7,284,000)
Change in Fair Value on Loans Held for Sale	102,000	(60,000)
Other assets	4,561,000	(42,044,000)
Increase (Decrease) in Other Operating Liabilities	6,177,000	18,314,000
Total adjustments	23,287,000	(19,695,000)
Net cash provided by operating activities	88,427,000	39,774,000
Cash flows used in investing activities
Proceeds from sales of securities available for sale	523,000	285,000
Proceeds from maturities and principal repayments of securities available for sale	40,228,000	48,421,000
Purchases of securities available for sale	(104,284,000)	(60,888,000)
Proceeds from maturities and principal repayments of securities held to maturity	58,308,000	62,005,000
Purchases of securities held to maturity	(49,802,000)	(14,998,000)
Net redemption of Federal Home Loan Bank stock	386,000	3,127,000
Investments in low income housing projects	(4,713,000)	(5,473,000)
Purchases of life insurance policies	(115,000)	(116,000)
Net increase in loans	(138,622,000)	(198,731,000)
Cash Acquired in Excess of Payments to Acquire Business	6,289,000	0
Purchases of bank premises and equipment	(18,643,000)	(6,022,000)
Proceeds from the sale of bank premises and equipment	1,919,000	26,000
Proceeds from the sale of other real estate owned and foreclosed assets	1,531,000	842,000
Net payments relating to other real estate owned and foreclosed assets	0	(145,000)
Net cash used in investing activities	(206,995,000)	(171,667,000)
Cash flows provided by financing activities
Net decrease in time deposits	(35,947,000)	(55,759,000)
Net increase in other deposits	147,331,000	334,516,000
Repayments of long-term Federal Home Loan Bank borrowings	0	(51,641,000)
Net increase in customer repurchase agreements	2,757,000	6,956,000
Payments for Repurchase of Common Stock	(5,000)
Proceeds from exercise of stock options, net of cash paid		160,000
Restricted stock awards issued, net of awards surrendered	(1,363,000)	(673,000)
Excess tax benefit from stock based compensation		354,000
Tax benefit from deferred compensation distribution		179,000
Proceeds from shares issued under direct stock purchase plan	1,230,000	1,918,000
Common dividends paid	(25,265,000)	(22,079,000)
Net cash provided by financing activities	88,738,000	213,931,000
Net increase (decrease) in cash and cash equivalents	(29,830,000)	82,038,000
Cash and cash equivalents at beginning of year	289,095,000	275,765,000
Cash and cash equivalents at end of period	259,265,000	357,803,000
Supplemental schedule of noncash investing and financing activities
Real Estate Owned, Transfer from Real Estate Owned	564,000	377,000
Net increase in capital commitments relating to low income housing project investments	248,000	163,000
Stock Issued During Period, Value, Acquisitions	23,468,000	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	179,252,000	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	$ 162,073,000	$ 0