Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
INTEREST INCOME:
Interest and fees on loans	$ 82,906	$ 70,046	$ 217,898	$ 208,280
Interest on securities:
Taxable	10,394	7,917	27,246	24,604
Nontaxable	5,086	3,717	15,297	10,793
Interest on federal funds sold	34	1	37	12
Interest on interest bearing deposits in other financial institutions	558	6	1,112	13
TOTAL INTEREST INCOME	98,978	81,687	261,590	243,702
INTEREST EXPENSE:
Interest on deposits	5,073	4,001	12,966	12,195
Interest on short-term borrowings	271	235	498	1,083
Interest on other borrowings (includes $308 and $492 of interest expense related to derivatives reclassified from accumulated other comprehensive income for the three months ended September 30, 2017 and 2016, respectively, and $1,005 and $1,463 of interest expense related to derivatives reclassified from accumulated other comprehensive income for the nine months ended September 30, 2017 and 2016, respectively)	3,790	3,770	10,674	10,918
TOTAL INTEREST EXPENSE	9,134	8,006	24,138	24,196
NET INTEREST INCOME	89,844	73,681	237,452	219,506
Provision for loan losses	5,705	5,328	10,235	9,513
NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES	84,139	68,353	227,217	209,993
NONINTEREST INCOME:
Service charges and fees	10,138	8,278	29,291	23,462
Loan servicing income	1,161	873	4,236	3,433
Trust fees	3,872	3,689	11,482	11,127
Brokerage and insurance commissions	950	1,006	2,962	2,914
Securities gains, net (includes $1,679 and $1,586 of net security gains reclassified from accumulated other comprehensive income for the three months ended September 30, 2017 and 2016, respectively, $5,553 and $9,964 of net security gains reclassified from accumulated other comprehensive income for the nine months ended September 30, 2017 and 2016, respectively)	1,679	1,584	5,553	9,732
Net gains on sale of loans held for sale	4,997	11,459	17,961	33,794
Valuation allowance on commercial servicing rights	5	5	29	(41)
Income on bank owned life insurance	766	620	2,039	1,733
Other noninterest income	1,409	1,028	2,941	2,992
TOTAL NONINTEREST INCOME	24,977	28,542	76,494	89,146
NONINTEREST EXPENSES:
Salaries and employee benefits	45,225	40,733	128,118	124,432
Occupancy	6,223	5,099	16,352	15,322
Furniture and equipment	2,826	2,746	7,913	7,301
Professional fees	8,450	5,985	24,342	20,481
FDIC insurance assessments	894	1,180	2,610	3,468
Advertising	1,358	1,339	5,141	4,174
Core deposit intangibles and customer relationship intangibles amortization	1,863	1,291	4,252	4,483
Other real estate and loan collection expenses	581	640	1,774	1,871
Loss on sales/valuations of assets, net	1,342	794	1,642	1,064
Other noninterest expenses	9,997	8,620	27,653	27,160
TOTAL NONINTEREST EXPENSES	78,759	68,427	219,797	209,756
INCOME BEFORE INCOME TAXES	30,357	28,468	83,914	89,383
Income taxes (includes $511 and $408 of income tax expense reclassified from accumulated other comprehensive income for the three months ended September 30, 2017 and 2016, respectively, $1,696 and $3,171 of income tax expense reclassified from accumulated other comprehensive income for the nine months ended September 30, 2017 and 2016, respectively)	8,725	8,260	22,314	28,196
NET INCOME	21,632	20,208	61,600	61,187
Preferred dividends	(13)	(53)	(45)	(273)
Interest expense on convertible preferred debt	3	17	12	48
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS	$ 21,622	$ 20,172	$ 61,567	$ 60,962
EARNINGS PER COMMON SHARE - BASIC (in dollars per share)	$ 0.73	$ 0.82	$ 2.23	$ 2.51
EARNINGS PER COMMON SHARE - DILUTED (in dollars per share)	0.72	0.81	2.21	2.48
CASH DIVIDENDS DECLARED PER COMMON SHARE (in dollars per share)	$ 0.11	$ 0.10	$ 0.33	$ 0.30