Consolidated Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	$ 41,288,000	$ 38,985,000
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	7,454,000	7,242,000
Provision for loan losses	1,650,000	1,125,000
Deferred income tax expense	642,000	415,000
Net (gain) loss on sale of securities	(2,000)	27,000
Net (gain) loss on bank premises and equipment	(92,000)	13,000
Loss on extinguishment of debt	0	437,000
Net loss on other real estate owned and foreclosed assets	70,000	41,000
Realized gain on sale leaseback transaction	(517,000)	(517,000)
Stock based compensation	1,560,000	1,633,000
Excess tax benefit related to equity award activity	0	(327,000)
Increase in cash surrender value of life insurance policies	(1,981,000)	(1,996,000)
Change in fair value on loans held for sale	(6,000)	(13,000)
Net change in:
Trading assets	(489,000)	(443,000)
Loans held for sale	(3,236,000)	(6,924,000)
Other assets	8,973,000	(45,265,000)
Increase (Decrease) in Other Operating Liabilities	(6,104,000)	19,615,000
Total adjustments	7,922,000	(24,937,000)
Net cash provided by operating activities	49,210,000	14,048,000
Cash flows used in investing activities
Proceeds from sales of securities available for sale	35,000	285,000
Proceeds from maturities and principal repayments of securities available for sale	24,406,000	32,625,000
Purchases of securities available for sale	(74,956,000)	(46,358,000)
Proceeds from maturities and principal repayments of securities held to maturity	38,634,000	39,028,000
Purchases of securities held to maturity	(49,802,000)
Redemption (purchases) of Federal Home Loan Bank stock	(2,438,000)	3,127,000
Investments in low income housing projects	(3,871,000)	(4,431,000)
Purchases of life insurance policies	(101,000)	(101,000)
Net increase in loans	(118,579,000)	(126,406,000)
Purchases of bank premises and equipment	(14,182,000)	(4,003,000)
Proceeds from the sale of bank premises and equipment	1,918,000	14,000
Proceeds from the sale of other real estate owned and foreclosed assets	1,531,000	795,000
Net payments relating to other real estate owned and foreclosed assets	0	(145,000)
Net cash used in investing activities	(191,116,000)	(105,570,000)
Cash Acquired in Excess of Payments to Acquire Business	6,289,000	0
Cash flows provided by financing activities
Net decrease in time deposits	(55,787,000)	(40,755,000)
Net increase in other deposits	179,495,000	247,944,000
Repayments of long-term Federal Home Loan Bank borrowings	0	(51,641,000)
Net increase (decrease) in customer repurchase agreements	(17,542,000)	5,758,000
Net proceeds from exercise of stock options	8,000	144,000
Restricted stock awards issued, net of awards surrendered	(1,361,000)	(673,000)
Excess tax benefit from stock based compensation		327,000
Tax benefit from deferred compensation distribution		179,000
Proceeds from shares issued under direct stock purchase plan	807,000	1,060,000
Common dividends paid	(16,487,000)	(14,449,000)
Net cash provided by financing activities	89,133,000	147,894,000
Net increase (decrease) in cash and cash equivalents	(52,773,000)	56,372,000
Cash and cash equivalents at beginning of year	289,095,000	275,765,000
Cash and cash equivalents at end of period	236,322,000	332,137,000
Supplemental schedule of noncash investing and financing activities
Real Estate Owned, Transfer from Real Estate Owned	457,000	377,000
Net increase (decrease) in capital commitments relating to low income housing project investments	46,000	(180,000)
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