FAIR VALUE (Details) (USD $)	3 Months Ended		6 Months Ended				6 Months Ended								3 Months Ended				6 Months Ended				3 Months Ended		6 Months Ended
	Jun. 30, 2011		Jun. 30, 2011		Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Pooled Trust Preferred Securities [Member]	Jun. 30, 2012 Impaired Loans [Member]	Jun. 30, 2012 Other Real Estate Owned [Member]	Jun. 30, 2012 Mortgage Servicing Rights [Member]	Jun. 30, 2012 Carrying [Member]	Dec. 31, 2011 Carrying [Member]	Jun. 30, 2012 Fair Value Disclosure [Member]	Dec. 31, 2011 Fair Value Disclosure [Member]	Jun. 30, 2012 Pooled Trust Preferred Securities [Member]		Jun. 30, 2011 Pooled Trust Preferred Securities [Member]		Jun. 30, 2012 Pooled Trust Preferred Securities [Member]		Jun. 30, 2011 Pooled Trust Preferred Securities [Member]		Jun. 30, 2011 Commitments to Originate Real Estate Loans for Sale [Member]		Jun. 30, 2011 Commitments to Originate Real Estate Loans for Sale [Member]		Jun. 30, 2012 Recurring [Member]	Dec. 31, 2011 Recurring [Member]	Jun. 30, 2012 Recurring [Member] Level 1 [Member]	Dec. 31, 2011 Recurring [Member] Level 1 [Member]	Jun. 30, 2012 Recurring [Member] Level 2 [Member]	Dec. 31, 2011 Recurring [Member] Level 2 [Member]	Jun. 30, 2012 Recurring [Member] Level 3 [Member]	Dec. 31, 2011 Recurring [Member] Level 3 [Member]	Jun. 30, 2012 Nonrecurring [Member]	Dec. 31, 2011 Nonrecurring [Member]	Jun. 30, 2012 Nonrecurring [Member] Level 1 [Member]	Dec. 31, 2011 Nonrecurring [Member] Level 1 [Member]	Jun. 30, 2012 Nonrecurring [Member] Level 2 [Member]	Dec. 31, 2011 Nonrecurring [Member] Level 2 [Member]	Jun. 30, 2012 Nonrecurring [Member] Level 3 [Member]	Dec. 31, 2011 Nonrecurring [Member] Level 3 [Member]
Available-for-sale investment securities:
U.S. Treasury and agency securities																											$ 1,089,292,000	$ 520,548,000	$ 890,160,000	$ 311,958,000	$ 199,132,000	$ 208,590,000	$ 0	$ 0
Obligations of state and political subdivisions																											713,232,000	573,012,000	0	0	713,232,000	573,012,000	0	0
Government agency mortgage-backed securities																											298,314,000	331,379,000	0	0	298,314,000	331,379,000	0	0
Pooled trust preferred securities																											48,786,000	43,846,000	0	0	0	0	48,786,000	43,846,000
Government agency collateralized mortgage obligations																											39,910,000	46,943,000	0	0	39,910,000	46,943,000	0	0
Corporate debt securities																											16,231,000	22,855,000	0	0	16,231,000	22,855,000	0	0
Marketable equity securities																											382,000	390,000	382,000	390,000	0	0	0	0
Total available-for-sale investment securities					2,206,147,000	1,538,973,000																					2,206,147,000	1,538,973,000	890,542,000	312,348,000	1,266,819,000	1,182,779,000	48,786,000	43,846,000
Mortgage loans held for sale																												532,000		0		532,000		0
Total																												1,539,505,000		312,348,000		1,183,311,000		43,846,000
Assets and Liabilities Measured on Nonrecurring Basis [Abstract]
Impaired loans																																			2,487,000	4,118,000	0	0	0	0	2,487,000	4,118,000
Other real estate owned																																			2,899,000	2,682,000	0	0	0	0	2,899,000	2,682,000
Mortgage servicing rights																																			797,000	1,747,000	0	0	0	0	797,000	1,747,000
Total							48,786,000	6,423,000	2,899,000	797,000																									6,183,000	8,547,000	0	0	0	0	6,183,000	8,547,000
Impaired Loans Valuation Allowance					297,000
Discount on appraisal value of foreclosed real estate, minimum (in hundredths)					11.00%
Discount on appraisal value of foreclosed real estate, maximum (in hundredths)					68.00%
Level 3 Assets Measured at Fair Value on a Recurring Basis [Abstract]
Beginning balance	48,230,000		42,051,000												47,385,000		48,172,000		43,846,000		41,993,000		58,000		58,000
Total gains (losses) included in earnings	(33,000)	[1],[2]	(68,000)	[1],[2]											96,000	[1],[2]	25,000	[1],[2]	144,000	[1],[2]	48,000	[1],[2]	(58,000)	[1],[2]	(116,000)	[1],[2]
Total gains included in other comprehensive income	1,156,000	[3]	7,679,000	[3]											3,800,000	[3]	1,156,000	[3]	8,367,000	[3]	7,679,000	[3]	0	[3]	0	[3]
Principal reductions	(381,000)		(748,000)												(2,495,000)		(381,000)		(3,571,000)		(748,000)		0		0
Commitments to originate real estate loans held for sale, net	142,000		200,000												0		0		0		0		142,000		200,000
Ending balance	49,114,000		49,114,000												48,786,000		48,972,000		48,786,000		48,972,000		142,000		142,000
Financial assets:
Net loans											3,561,670,000	3,471,025,000	3,585,324,000	3,491,729,000
Financial liabilities:
Deposits											4,910,352,000	4,795,245,000	4,919,010,000	4,810,856,000
Borrowings											1,157,872,000	728,281,000	1,256,257,000	828,018,000
Subordinated debt held by unconsolidated subsidiary trusts											102,060,000	102,048,000	71,905,000	73,211,000
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure							$ 48,786,000	$ 6,423,000	$ 2,899,000	$ 797,000																									$ 6,183,000	$ 8,547,000	$ 0	$ 0	$ 0	$ 0	$ 6,183,000	$ 8,547,000
Pooled Trust Preferred Securities, Valuation Techniques							Consensus pricing
Impaired Loans, Valuation Techniques								Fair value of collateral
Other Real Estate Owned, Valuation Techniques									Fair value of collateral
Mortgage Servicing Rights, Valuation Techniques										Discounted cash flow
Significant Unobservable Inputs, Inputs Description							Weighting of offered quotes	Estimated cost of disposal	Estimated cost of disposal	Weighted average constant prepayment rate
Significant Unobservable Input Range, Minimum (in hundredths)							56.30%	11.00%	11.00%
Significant Unobservable Input Range, Maximum (in hundredths)							83.50%	25.00%	69.00%
Significant Unobservable Input Range, Weighted Average Fair Value (in hundredths)							73.80%	18.00%	22.00%
Constant Prepayment Input Range Minimum (in hundredths)										17.10%
Constant Prepayment Input Range Maximum (in hundredths)										32.30%
Constant Prepayment Input Range Weighted Average (in hundredths)										26.50%
Weighted average discount rate Input Range Minimum (in hundredths)										2.42%
Weighted average discount rate Input Range Maximum (in hundredths)										3.13%
Weighted average discount rate Input Range Weighted Average (in hundredths)										2.95%
Adequate Compensation Input Range										$7/loan

[1] Amounts included in earnings associated with the commitments to originate real estate loans for sale are reported as a component of other banking service fees.

[2] Amounts included in earnings associated with the pooled trust preferred securities relate to accretion of related discount and are reported in interest and dividends on taxable investments.

[3] Amounts included in other comprehensive income associated with the pooled trust preferred securities are relate to changes in unrealized loss and are reported as a component of unrealized gains on securities in the Statement of Comprehensive Income.