CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Interest income:
Interest and fees on loans	$ 47,040	$ 46,883	$ 138,422	$ 138,649
Interest and dividends on taxable investments	13,454	12,239	38,802	37,481
Interest and dividends on nontaxable investments	4,790	5,165	14,394	15,505
Total interest income	65,284	64,287	191,618	191,635
Interest expense:
Interest on deposits	1,694	1,962	5,225	6,265
Interest on borrowings	587	308	1,081	846
Interest on subordinated debt held by unconsolidated subsidiary trusts	640	623	1,881	1,852
Total interest expense	2,921	2,893	8,187	8,963
Net interest income	62,363	61,394	183,431	182,672
Provision for loan losses	1,906	1,747	3,120	4,647
Net interest income after provision for loan losses	60,457	59,647	180,311	178,025
Noninterest revenues:
Deposit service fees	13,459	13,833	39,142	39,260
Other banking services	2,045	1,867	3,899	4,665
Employee benefit services	11,330	10,755	33,727	31,638
Wealth management services	4,552	4,617	13,383	13,529
Total noninterest revenues	31,386	31,072	90,151	89,092
Noninterest expenses:
Salaries and employee benefits	31,179	30,941	93,218	92,090
Occupancy and equipment	6,652	6,617	20,891	21,224
Data processing and communications	7,643	7,475	22,106	21,529
Amortization of intangible assets	843	1,051	2,642	3,293
Legal and professional fees	1,564	1,973	4,952	5,427
Office supplies and postage	1,636	1,466	4,733	4,664
Business development and marketing	1,889	1,764	5,711	5,424
FDIC insurance premiums	968	952	2,920	2,918
Acquisition expenses and litigation settlement	562	2,800	1,318	2,923
Other	3,143	3,772	9,584	10,404
Total noninterest expenses	56,079	58,811	168,075	169,896
Income before income taxes	35,764	31,908	102,387	97,221
Income taxes	10,742	9,537	31,228	29,001
Net income	$ 25,022	$ 22,371	$ 71,159	$ 68,220
Basic earnings per share (in dollars per share)	$ 0.61	$ 0.55	$ 1.74	$ 1.67
Diluted earnings per share (in dollars per share)	0.60	0.54	1.72	1.65
Cash dividends declared per share (in dollars per share)	$ 0.31	$ 0.30	$ 0.91	$ 0.86