Consolidated Statements of Earnings (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
INTEREST INCOME:
Interest and fees on loans	$ 35,061	$ 33,058
Interest on investment securities:
Taxable	7,808	7,084
Exempt from federal income tax	9,120	7,980
Interest on federal funds sold and interest-bearing deposits in banks	80	87
Total interest income	52,069	48,209
INTEREST EXPENSE:
Interest on deposits	928	940
Other	42	96
Total interest expense	970	1,036
Net interest income	51,099	47,173
PROVISION FOR LOAN LOSSES	1,290	1,690
Net interest income after provision for loan losses	49,809	45,483
NONINTEREST INCOME:
Trust fees	4,731	4,576
Service charges on deposit accounts	3,768	4,047
ATM, interchange and credit card fees	4,969	4,443
Real estate mortgage operations	1,427	1,024
Net gain (loss) on sale of available-for-sale securities (includes $5 and ($4) for the three months ended March 31, 2015 and 2014, respectively, related to accumulated other comprehensive earnings reclassifications)	5	(4)
Net gain (loss) on sale of foreclosed assets	30	452
Other	967	1,867
Total noninterest income	15,897	16,405
NONINTEREST EXPENSE:
Salaries and employee benefits	18,265	17,414
Net occupancy expense	2,197	2,234
Equipment expense	2,899	2,622
FDIC insurance premiums	748	659
ATM, interchange and credit card expenses	1,725	1,480
Professional and service fees	1,065	1,080
Printing, stationery and supplies	596	775
Amortization of intangible assets	90	75
Other	6,358	6,109
Total noninterest expense	33,943	32,448
EARNINGS BEFORE INCOME TAXES	31,763	29,440
INCOME TAX EXPENSE (includes $2 and ($1) for the three months ended March 31, 2015 and 2014, respectively, related to income tax expense reclassification)	7,766	7,104
NET EARNINGS	$ 23,997	$ 22,336
EARNINGS PER SHARE, BASIC	$ 0.37	$ 0.35
EARNINGS PER SHARE, ASSUMING DILUTION	$ 0.37	$ 0.35
DIVIDENDS PER SHARE	$ 0.14	$ 0.13