ALLOWANCE FOR LOAN AND LEASE LOSSES - Additional Information (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for loan and lease losses	$ 9,042,000	$ 5,283,000	$ 6,622,000	$ 6,047,000	$ 12,951,000
Net charge-offs	8,700,000				9,600,000
FDIC loss sharing income	8,934,000				12,816,000
Allowance for covered loan losses	45,496,000	45,190,000	48,895,000	48,327,000	46,156,000	42,835,000
Loss sharing expense	2,286,000				1,751,000
Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance threshold for impaired and non-impaired commercial loans	250,000
Covered Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Loss sharing expense	2,100,000				3,000,000
Commercial Loan [Member] | Non Covered Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Restructured Loans, Loan Relationships, Review Threshold Amount Minimum	250,000
Residential Portfolio Segment [Member] | Non Covered Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Restructured Loans, Loan Relationships, Review Threshold Amount Minimum	$ 100,000