GOODWILL AND OTHER INTANGIBLE ASSETS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Carrying amounts of goodwill [Roll Forward]
Balance, beginning of period	$ 271,297	$ 270,097
Goodwill recorded during the year	3,876	1,200
Balance, end of period	275,173	271,297	270,097
Amortized intangible assets [Abstract]
Gross Carrying Amount	64,565	60,625
Accumulated Amortization	47,923	44,701
Aggregate amortization expense [Abstract]
Total	3,222	3,324	3,909
Estimated Amortization Expense:
For year ending December 31, 2013	2,833
For year ending December 31, 2014	2,496
For year ending December 31, 2015	2,059
For year ending December 31, 2016	1,612
For year ending December 31, 2017	1,411
Trade names [Member]
Unamortized intangible assets [Abstract]
Gross Carrying Amount	688	688
Core deposit intangibles [Member]
Amortized intangible assets [Abstract]
Gross Carrying Amount	27,801	27,801
Accumulated Amortization	21,674	20,728
Aggregate amortization expense [Abstract]
Total	946	1,012
Estimated Amortization Expense:
For year ending December 31, 2013	582
For year ending December 31, 2014	526
For year ending December 31, 2015	487
For year ending December 31, 2016	451
For year ending December 31, 2017	419
Customer relationship intangibles [Member]
Amortized intangible assets [Abstract]
Gross Carrying Amount	36,239	32,749
Accumulated Amortization	26,098	23,935
Aggregate amortization expense [Abstract]
Total	2,163	2,274
Estimated Amortization Expense:
For year ending December 31, 2013	2,101
For year ending December 31, 2014	1,820
For year ending December 31, 2015	1,497
For year ending December 31, 2016	1,161
For year ending December 31, 2017	992
Non-solicitation intangibles [Member]
Amortized intangible assets [Abstract]
Gross Carrying Amount	525	75
Accumulated Amortization	151	38
Aggregate amortization expense [Abstract]
Total	113	38
Estimated Amortization Expense:
For year ending December 31, 2013	150
For year ending December 31, 2014	150
For year ending December 31, 2015	75
For year ending December 31, 2016	0
For year ending December 31, 2017	0
Community Banking [Member]
Carrying amounts of goodwill [Roll Forward]
Balance, beginning of period	217,618	217,618
Goodwill recorded during the year	0	0
Balance, end of period	217,618	217,618
Percentage of fair value over carrying value for goodwill impairment analysis (in hundredths)	23.00%
Insurance Agencies [Member]
Carrying amounts of goodwill [Roll Forward]
Balance, beginning of period	53,679	52,479
Goodwill recorded during the year	3,876	1,200
Balance, end of period	$ 57,555	$ 53,679
Percentage of fair value over carrying value for goodwill impairment analysis (in hundredths)	26.00%