Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest income:
Loans, including fees	$ 224,332	$ 199,702	$ 645,340	$ 566,663
Loans held for sale	268	216	784	669
Securities-taxable	32,482	26,616	92,566	74,385
Securities-tax exempt	5,461	5,608	16,488	16,643
Short-term investments	669	574	1,733	3,048
Total interest income	263,212	232,716	756,911	661,408
Interest expense:
Deposits	34,190	21,789	91,019	52,972
Short-term borrowings	11,780	4,425	24,547	11,598
Long-term debt	3,048	3,645	9,940	12,573
Total interest expense	49,018	29,859	125,506	77,143
Net interest income	214,194	202,857	631,405	584,265
Provision for loan losses	6,872	13,040	28,016	43,982
Net interest income after provision for loan losses	207,322	189,817	603,389	540,283
Noninterest income:
Service charges on deposit accounts	21,377	21,444	63,806	60,711
Trust fees	16,738	10,742	39,726	33,459
Bank card and ATM fees	14,862	13,390	44,784	39,545
Investment and annuity fees and insurance commissions	6,652	6,230	19,041	17,939
Secondary mortgage market operations	4,333	4,157	11,699	11,965
Other income	11,556	11,152	31,546	34,474
Total noninterest income	75,518	67,115	210,602	198,093
Noninterest expense:
Compensation expense	84,389	82,242	244,374	237,486
Employee benefits	18,084	16,901	55,316	54,869
Personnel expense	102,473	99,143	299,690	292,355
Net occupancy expense	11,895	12,448	35,221	36,285
Equipment expense	4,520	3,779	12,328	11,457
Data processing expense	20,492	16,798	55,214	48,993
Professional services expense	9,555	10,062	32,191	31,691
Amortization of intangible assets	5,638	6,070	16,578	16,532
Telecommunications and postage	3,598	3,876	11,063	11,081
Deposit insurance and regulatory fees	8,345	7,883	24,669	21,356
Other real estate (income) expense	16	199	(63)	(2,329)
Other expense	14,655	17,358	49,489	57,207
Total noninterest expense	181,187	177,616	536,380	524,628
Income before income taxes	101,653	79,316	277,611	213,748
Income taxes	17,775	20,414	50,081	53,565
Net income	$ 83,878	$ 58,902	$ 227,530	$ 160,183
Earnings per common share-basic	$ 0.96	$ 0.68	$ 2.62	$ 1.85
Earnings per common share-diluted	0.96	0.68	2.61	1.85
Dividends paid per share	$ 0.27	$ 0.24	$ 0.75	$ 0.72
Weighted average shares outstanding-basic	85,348	84,749	85,298	84,577
Weighted average shares outstanding-diluted	85,539	84,980	85,482	84,818