FAIR VALUE MEASUREMENTS (Details 5) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Financial Assets
Securities available for sale	$ 568,268,000	$ 466,169,000
Derivative assets	8,063,000	14,746,000
Financial Liabilities
Derivative liabilities	(16,141,000)	(29,814,000)
Unrealized losses on forward commitments	1,500,000	1,300,000
Methods and assumptions used to estimate the fair value of significant classes of financial instruments
Junior subordinated debentures re-price period	90 days
Level 1
Financial Assets
Cash and cash equivalents	56,623,000	63,382,000
Securities available for sale	31,260,000	25,291,000
Derivative assets	3,510,000
Financial Liabilities
Derivative liabilities		282,000
Level 2
Financial Assets
Securities available for sale	535,190,000	439,993,000
Restricted equity securities	37,667,000	39,785,000
Loans held for sale	64,101,000	85,368,000
Accrued interest receivable	14,741,000	14,731,000
Cash surrender value of bank-owned life insurance policies	89,592,000	88,198,000
Derivative assets	8,651,000	14,746,000
Financial Liabilities
Total deposits	3,818,846,000	4,116,999,000
Short-term debt	415,753,000	163,150,000
Long-term Federal Home Loan Bank advances	177,691,000	199,420,000
Subordinated notes	75,750,000	73,967,000
Derivative liabilities	14,594,000	29,818,000
Level 3
Financial Assets
Trading security	15,566,000	16,893,000
Securities available for sale	1,818,000	885,000
Securities held to maturity	50,056,000	51,024,000
Net loans	3,883,256,000	4,044,259,000
Derivative assets	1,403,000	6,258,000
Financial Liabilities
Derivative liabilities	1,507,000	1,055,000
Carrying Amount
Financial Assets
Cash and cash equivalents	56,623,000	63,382,000
Trading security	15,566,000	16,893,000
Securities available for sale	568,268,000	466,169,000
Securities held to maturity	49,604,000	51,024,000
Restricted equity securities	37,667,000	39,785,000
Net loans	3,837,427,000	3,955,446,000
Loans held for sale	64,101,000	85,368,000
Accrued interest receivable	14,741,000	14,731,000
Cash surrender value of bank-owned life insurance policies	89,592,000	88,198,000
Derivative assets	13,564,000	21,004,000
Financial Liabilities
Total deposits	3,815,223,000	4,104,402,000
Short-term debt	415,720,000	163,150,000
Long-term Federal Home Loan Bank advances	175,106,000	195,321,000
Subordinated notes	89,647,000	89,617,000
Derivative liabilities	16,101,000	31,155,000
Fair Value
Financial Assets
Cash and cash equivalents	56,623,000	63,382,000
Trading security	15,566,000	16,893,000
Securities available for sale	568,268,000	466,169,000
Securities held to maturity	50,056,000	51,024,000
Restricted equity securities	37,667,000	39,785,000
Net loans	3,883,256,000	4,004,259,000
Loans held for sale	64,101,000	85,368,000
Accrued interest receivable	14,741,000	14,731,000
Cash surrender value of bank-owned life insurance policies	89,592,000	88,198,000
Derivative assets	13,564,000	21,004,000
Financial Liabilities
Total deposits	3,818,846,000	4,116,999,000
Short-term debt	415,753,000	163,150,000
Long-term Federal Home Loan Bank advances	177,691,000	199,420,000
Subordinated notes	75,750,000	73,967,000
Derivative liabilities	$ 16,101,000	$ 31,155,000