LOANS (excluding covered loans) - Loan Delinquency, including Nonaccrual Loans (Details) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans, excluding covered loans	$ 3,382,128,000	$ 3,179,064,000
Non Covered Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	14,660,000	12,367,000
60 - 89 days past due	3,322,000	5,411,000
> 90 days past due	48,800,000	41,660,000
Total Past due	66,782,000	59,438,000
Current	3,315,346,000	3,119,626,000
Total loans, excluding covered loans	3,382,128,000	3,179,064,000
> 90 days past due and still accruing	158,000	212,000
Non Covered Loans | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	723,000	1,770,000
60 - 89 days past due	3,000	832,000
> 90 days past due	10,551,000	4,197,000
Total Past due	11,277,000	6,799,000
Current	929,143,000	854,234,000
Total loans, excluding covered loans	940,420,000	861,033,000
> 90 days past due and still accruing	0	0
Non Covered Loans | Real estate-construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	0	0
60 - 89 days past due	0	0
> 90 days past due	1,104,000	892,000
Total Past due	1,104,000	892,000
Current	96,142,000	72,625,000
Total loans, excluding covered loans	97,246,000	73,517,000
> 90 days past due and still accruing	0	0
Non Covered Loans | Real estate-commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	7,397,000	2,549,000
60 - 89 days past due	2,504,000	1,931,000
> 90 days past due	28,314,000	27,966,000
Total Past due	38,215,000	32,446,000
Current	1,439,011,000	1,384,562,000
Total loans, excluding covered loans	1,477,226,000	1,417,008,000
> 90 days past due and still accruing	0	0
Non Covered Loans | Real estate-residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans, excluding covered loans	343,016,000	318,210,000
Non Covered Loans | Real estate - residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	4,618,000	6,071,000
60 - 89 days past due	0	1,463,000
> 90 days past due	6,460,000	6,113,000
Total Past due	11,078,000	13,647,000
Current	331,938,000	304,563,000
Total loans, excluding covered loans	343,016,000	318,210,000
> 90 days past due and still accruing	0	0
Non Covered Loans | Installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	414,000	280,000
60 - 89 days past due	131,000	148,000
> 90 days past due	197,000	344,000
Total Past due	742,000	772,000
Current	50,039,000	56,038,000
Total loans, excluding covered loans	50,781,000	56,810,000
> 90 days past due and still accruing	0	0
Non Covered Loans | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	1,247,000	1,311,000
60 - 89 days past due	524,000	869,000
> 90 days past due	1,520,000	1,440,000
Total Past due	3,291,000	3,620,000
Current	366,915,000	363,880,000
Total loans, excluding covered loans	370,206,000	367,500,000
> 90 days past due and still accruing	0	0
Non Covered Loans | All other
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	261,000	386,000
60 - 89 days past due	160,000	168,000
> 90 days past due	654,000	708,000
Total Past due	1,075,000	1,262,000
Current	102,158,000	83,724,000
Total loans, excluding covered loans	103,233,000	84,986,000
> 90 days past due and still accruing	$ 158,000	$ 212,000