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GOODWILL AND OTHER INTANGIBLE ASSETS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Carrying amounts of goodwill [Roll Forward]
Balance, beginning of period			$ 270,097
Balance, end of period	271,297	270,097	271,297	270,097
Minimum percentage of fair value over carrying value for goodwill impairment analysis (in hundredths)	15.00%		15.00%
Amortized intangible assets:
Gross Carrying Amount	60,625	60,312	60,625	60,312
Accumulated Amortization	43,064	41,377	43,064	41,377
Aggregate amortization expense [Abstract]
Total	832	984	1,687	1,999
Community Banking [Member]
Carrying amounts of goodwill [Roll Forward]
Balance, beginning of period			217,618
Goodwill recorded during the period			0
Balance, end of period	217,618		217,618
Insurance Agencies [Member]
Carrying amounts of goodwill [Roll Forward]
Balance, beginning of period			52,479
Goodwill recorded during the period			1,200
Balance, end of period	53,679		53,679
Core deposit intangibles [Member]
Amortized intangible assets:
Gross Carrying Amount	27,801		27,801		27,801
Accumulated Amortization	20,231		20,231		19,716
Aggregate amortization expense [Abstract]
Total	248	323	515	662
Estimated Amortization Expense:
For year ending December 31, 2011			1,016
For year ending December 31, 2012			946
For year ending December 31, 2013			582
For year ending December 31, 2014			526
For year ending December 31, 2015			157
Customer relationship intangibles [Member]
Amortized intangible assets:
Gross Carrying Amount	32,749		32,749		32,511
Accumulated Amortization	22,814		22,814		21,661
Aggregate amortization expense [Abstract]
Total	575	661	1,153	1,337
Estimated Amortization Expense:
For year ending December 31, 2011			2,223
For year ending December 31, 2012			1,905
For year ending December 31, 2013			1,632
For year ending December 31, 2014			1,398
For year ending December 31, 2015			1,136
Non-solicitation intangibles [Member]
Amortized intangible assets:
Gross Carrying Amount	75		75		0
Accumulated Amortization	19		19		0
Aggregate amortization expense [Abstract]
Total	9	0	19	0
Estimated Amortization Expense:
For year ending December 31, 2011			38
For year ending December 31, 2012			37
For year ending December 31, 2013			0
For year ending December 31, 2014			0
For year ending December 31, 2015			0
Trade names [Member]
Unamortized intangible assets:
Gross Carrying Amount	$ 688		$ 688		$ 688