Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Interest income:
Loans, including fees	$ 215,161	$ 194,180	$ 421,008	$ 366,961
Loans held for sale	295	236	516	453
Securities-taxable	30,783	24,402	60,084	47,769
Securities-tax exempt	5,490	5,628	11,027	11,035
Short-term investments	575	1,731	1,064	2,474
Total interest income	252,304	226,177	493,699	428,692
Interest expense:
Deposits	29,870	18,364	56,829	31,183
Short-term borrowings	7,416	4,232	12,767	7,173
Long-term debt	3,471	3,864	6,892	8,928
Total interest expense	40,757	26,460	76,488	47,284
Net interest income	211,547	199,717	417,211	381,408
Provision for loan losses	8,891	14,951	21,144	30,942
Net interest income after provision for loan losses	202,656	184,766	396,067	350,466
Noninterest income:
Service charges on deposit accounts	20,981	20,061	42,429	39,267
Trust fees	11,653	11,506	22,988	22,717
Bank card and ATM fees	15,464	13,687	29,922	26,155
Investment and annuity fees and insurance commissions	6,264	6,445	12,389	11,709
Secondary mortgage market operations	3,965	4,241	7,366	7,808
Other income	10,505	11,547	19,990	23,322
Total noninterest income	68,832	67,487	135,084	130,978
Noninterest expense:
Compensation expense	79,885	82,145	159,985	155,244
Employee benefits	17,358	18,888	37,232	37,968
Personnel expense	97,243	101,033	197,217	193,212
Net occupancy expense	12,316	13,080	23,326	23,837
Equipment expense	4,262	3,964	7,808	7,678
Data processing expense	18,273	16,798	34,722	32,195
Professional services expense	13,381	10,353	22,636	21,629
Amortization of intangible assets	5,322	5,757	10,940	10,462
Telecommunications and postage	3,615	3,738	7,465	7,205
Deposit insurance and regulatory fees	8,376	6,983	16,324	13,473
Other real estate income	(289)	(2,515)	(79)	(2,528)
Other expense	21,903	24,279	34,834	39,849
Total noninterest expense	184,402	183,470	355,193	347,012
Income before income taxes	87,086	68,783	175,958	134,432
Income taxes	15,909	16,516	32,306	33,151
Net income	$ 71,177	$ 52,267	$ 143,652	$ 101,281
Earnings per common share-basic	$ 0.82	$ 0.60	$ 1.65	$ 1.17
Earnings per common share-diluted	0.82	0.60	1.65	1.17
Dividends paid per share	$ 0.24	$ 0.24	$ 0.48	$ 0.48
Weighted average shares outstanding-basic	85,305	84,614	85,273	84,489
Weighted average shares outstanding-diluted	85,483	84,867	85,451	84,755