FAIR VALUE MEASUREMENTS (Details 5) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Financial Assets:
Interest-earning deposits in financial institutions	$ 75,393,000	$ 203,275,000
Loans and leases, net	3,498,329,000	3,425,423,000
Financial Liabilities:
Time deposits	820,327,000
Non-covered impaired loans
Nonaccrual loans	39,300,000	58,300,000
Amount of nonaccrual loans writtendown to fair values through chargeoffs	8,600,000
Other real estate owned
Period of appraisals for Level 2 measurement	12 months
Minimum
Non-covered impaired loans
Threshold of unpaid principal balance of non-covered nonaccrual loans for individual evaluation of impairment	250,000
Maximum
Non-covered impaired loans
Threshold of unpaid principal balance of non-covered nonaccrual loans for collective evaluation of impairment	250,000
Total
Financial Assets:
Cash and due from banks	89,011,000	92,342,000
Interest-earning deposits in financial institutions	75,393,000	203,275,000
Securities available-for-sale	1,355,385,000	1,326,358,000
Investment in FHLB stock	37,126,000	46,106,000
Loans and leases, net	3,551,674,000	3,469,754,000
SBA loan servicing asset	1,000,000	1,613,000
Financial Liabilities:
Demand, money market and savings deposits	3,888,794,000	3,609,559,000
Time deposits	823,912,000	977,589,000
Borrowings	12,611,000	249,000,000
Subordinated debentures	108,186,000	135,532,000
Level 1
Financial Assets:
Cash and due from banks	89,011,000	92,342,000
Interest-earning deposits in financial institutions	75,393,000	203,275,000
Securities available-for-sale	8,985,000	2,976,000
Level 2
Financial Assets:
Securities available-for-sale	1,301,716,000	1,278,233,000
Investment in FHLB stock	37,126,000	46,106,000
Loans and leases, net	4,975,000	13,803,000
Financial Liabilities:
Demand, money market and savings deposits	3,888,794,000	3,609,559,000
Time deposits	823,912,000	977,589,000
Borrowings	12,611,000	249,000,000
Subordinated debentures	108,186,000	135,532,000
Level 3
Financial Assets:
Securities available-for-sale	44,684,000	45,149,000
Loans and leases, net	3,546,699,000	3,455,951,000
SBA loan servicing asset	1,000,000	1,613,000
Carrying or Contract Amount
Financial Assets:
Cash and due from banks	89,011,000	92,342,000
Interest-earning deposits in financial institutions	75,393,000	203,275,000
Securities available-for-sale	1,355,385,000	1,326,358,000
Investment in FHLB stock	37,126,000	46,106,000
Loans and leases, net	3,498,329,000	3,425,423,000
SBA loan servicing asset	1,000,000	1,613,000
Financial Liabilities:
Demand, money market and savings deposits	3,888,794,000	3,609,559,000
Time deposits	820,327,000	967,894,000
Borrowings	12,591,000	225,000,000
Subordinated debentures	$ 108,250,000	$ 129,271,000