SEGMENT REPORTING (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Results of Operations [Abstract]
Net interest revenue	$ 435,682	$ 416,662	$ 398,949
Provision for credit losses	(13,000)		7,500
Net interest revenue, after provision for credit losses	448,682	416,662	391,449
Noninterest revenue	277,968	269,146	275,066
Noninterest expense	539,911	518,406	534,849
Income before income taxes	186,739	167,402	131,666
Income tax expense (benefit)	59,248	50,652	37,551
Net Income	127,491	116,750	94,115
Selected Financial Information [Abstract]
Total assets at end of period	13,798,662	13,326,369	13,029,733
Depreciation and amortization	30,251	31,715	29,523
Community Banking [Member]
Results of Operations [Abstract]
Net interest revenue	397,204	381,467	371,940
Provision for credit losses	(12,859)	(4,757)	5,824
Net interest revenue, after provision for credit losses	410,063	386,224	366,116
Noninterest revenue	82,938	95,752	95,573
Noninterest expense	332,920	329,893	311,554
Income before income taxes	160,081	152,083	150,135
Income tax expense (benefit)	51,186	47,482	46,135
Net Income	108,895	104,601	104,000
Selected Financial Information [Abstract]
Total assets at end of period	10,127,861	9,814,879	9,803,073
Depreciation and amortization	21,874	22,603	22,234
Insurance Agencies [Member]
Results of Operations [Abstract]
Net interest revenue	100	117	165
Net interest revenue, after provision for credit losses	100	117	165
Noninterest revenue	116,780	115,541	99,103
Noninterest expense	101,120	97,620	86,557
Income before income taxes	15,760	18,038	12,711
Income tax expense (benefit)	6,363	7,255	5,175
Net Income	9,397	10,783	7,536
Selected Financial Information [Abstract]
Total assets at end of period	199,668	188,920	187,424
Depreciation and amortization	4,736	5,257	3,655
General Corporate and Other [Member]
Results of Operations [Abstract]
Net interest revenue	38,378	35,078	26,844
Provision for credit losses	(141)	4,757	1,676
Net interest revenue, after provision for credit losses	38,519	30,321	25,168
Noninterest revenue	78,250	57,853	80,390
Noninterest expense	105,871	90,893	136,738
Income before income taxes	10,898	(2,719)	(31,180)
Income tax expense (benefit)	1,699	(4,085)	(13,759)
Net Income	9,199	1,366	(17,421)
Selected Financial Information [Abstract]
Total assets at end of period	3,471,133	3,322,570	3,039,236
Depreciation and amortization	$ 3,641	$ 3,855	$ 3,634