CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Interest income:
Interest and fees on loans	$ 45,791	$ 46,073	$ 91,382	$ 91,766
Interest and dividends on taxable investments	13,288	12,772	25,348	25,242
Interest and dividends on nontaxable investments	4,801	5,264	9,604	10,340
Total interest income	63,880	64,109	126,334	127,348
Interest expense:
Interest on deposits	1,731	2,068	3,531	4,303
Interest on borrowings	294	254	494	537
Interest on subordinated debt held by unconsolidated subsidiary trusts	627	617	1,241	1,229
Total interest expense	2,652	2,939	5,266	6,069
Net interest income	61,228	61,170	121,068	121,279
Provision for loan losses	591	1,900	1,214	2,900
Net interest income after provision for loan losses	60,637	59,270	119,854	118,379
Noninterest income:
Deposit service fees	13,213	13,172	25,683	25,427
Other banking services	799	1,608	1,854	2,798
Employee benefit services	11,322	10,448	22,397	20,883
Wealth management services	4,385	4,438	8,831	8,912
Total noninterest income	29,719	29,666	58,765	58,020
Noninterest expenses:
Salaries and employee benefits	31,010	30,409	62,039	61,149
Occupancy and equipment	6,844	6,916	14,239	14,608
Data processing and communications	7,473	7,251	14,463	14,054
Amortization of intangible assets	880	1,101	1,799	2,242
Legal and professional fees	1,642	1,507	3,388	3,454
Office supplies and postage	1,517	1,647	3,097	3,198
Business development and marketing	2,258	1,930	3,822	3,660
FDIC insurance premiums	963	947	1,952	1,966
Acquisition expenses	361	0	756	123
Other	3,100	3,456	6,441	6,632
Total noninterest expenses	56,048	55,164	111,996	111,086
Income before income taxes	34,308	33,772	66,623	65,313
Income taxes	10,468	10,096	20,486	19,463
Net income	$ 23,840	$ 23,676	$ 46,137	$ 45,850
Basic earnings per share (in dollars per share)	$ 0.58	$ 0.58	$ 1.13	$ 1.13
Diluted earnings per share (in dollars per share)	0.58	0.57	1.12	1.11
Cash dividends declared per share (in dollars per share)	$ 0.30	$ 0.28	$ 0.60	$ 0.56