LOANS (excluding covered loans) - Investment in Impaired Loans (Detail) (Non Covered Loans, USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Financing Receivable, Impaired [Line Items]
Restructured Loans, Accrual Status	$ 9,495,000	$ 4,009,000
Restructed Loans, Allowance for Loan and Lease Losses Included in Reserves	4,500,000	4,300,000
Recorded Investment	82,645,000	76,379,000
Contractual Principal Balance	107,312,000	101,881,000
Related Allowance	11,079,000	12,539,000
Average Recorded Investment	79,513,000	77,465,000
Interest Income Recognized	292,000	767,000
Commercial
Financing Receivable, Impaired [Line Items]
Recorded Investment	12,671,000	10,482,000
Contractual Principal Balance	15,830,000	12,654,000
Related Allowance	1,989,000	3,205,000
Average Recorded Investment	11,577,000	11,020,000
Interest Income Recognized	70,000	77,000
Real estate-construction
Financing Receivable, Impaired [Line Items]
Recorded Investment	12,733,000	17,387,000
Contractual Principal Balance	19,455,000	25,034,000
Related Allowance	2,333,000	2,578,000
Average Recorded Investment	15,060,000	19,388,000
Interest Income Recognized	50,000	94,000
Real estate-commercial
Financing Receivable, Impaired [Line Items]
Recorded Investment	44,220,000	34,520,000
Contractual Principal Balance	57,598,000	49,075,000
Related Allowance	6,453,000	6,441,000
Average Recorded Investment	39,370,000	33,790,000
Interest Income Recognized	142,000	474,000
Real estate-residential
Financing Receivable, Impaired [Line Items]
Recorded Investment	10,513,000	11,331,000
Contractual Principal Balance	11,753,000	12,285,000
Related Allowance	304,000	313,000
Average Recorded Investment	10,922,000	10,478,000
Interest Income Recognized	27,000	103,000
Installment
Financing Receivable, Impaired [Line Items]
Recorded Investment	492,000	485,000
Contractual Principal Balance	524,000	526,000
Related Allowance	0	0
Average Recorded Investment	489,000	371,000
Interest Income Recognized	1,000	6,000
Home equity
Financing Receivable, Impaired [Line Items]
Recorded Investment	2,016,000	2,174,000
Contractual Principal Balance	2,152,000	2,307,000
Related Allowance	0	2,000
Average Recorded Investment	2,095,000	2,418,000
Interest Income Recognized	2,000	13,000
Loans with an allowance recorded | Commercial
Financing Receivable, Impaired [Line Items]
Recorded Investment	2,878,000	4,131,000
Contractual Principal Balance	3,889,000	4,267,000
Related Allowance	1,989,000	3,205,000
Average Recorded Investment	3,505,000	3,683,000
Interest Income Recognized	15,000	15,000
Loans with an allowance recorded | Real estate-construction
Financing Receivable, Impaired [Line Items]
Recorded Investment	7,776,000	11,098,000
Contractual Principal Balance	12,034,000	13,905,000
Related Allowance	2,333,000	2,578,000
Average Recorded Investment	9,437,000	13,731,000
Interest Income Recognized	45,000	92,000
Loans with an allowance recorded | Real estate-commercial
Financing Receivable, Impaired [Line Items]
Recorded Investment	31,099,000	19,521,000
Contractual Principal Balance	35,823,000	26,357,000
Related Allowance	6,453,000	6,441,000
Average Recorded Investment	25,310,000	15,484,000
Interest Income Recognized	107,000	225,000
Loans with an allowance recorded | Real estate-residential
Financing Receivable, Impaired [Line Items]
Recorded Investment	2,474,000	2,692,000
Contractual Principal Balance	2,489,000	2,705,000
Related Allowance	304,000	313,000
Average Recorded Investment	2,583,000	3,630,000
Interest Income Recognized	11,000	37,000
Loans with an allowance recorded | Installment
Financing Receivable, Impaired [Line Items]
Recorded Investment	0	0
Contractual Principal Balance	0	0
Related Allowance	0	0
Average Recorded Investment	0	15,000
Interest Income Recognized	0	1,000
Loans with an allowance recorded | Home equity
Financing Receivable, Impaired [Line Items]
Recorded Investment	0	101,000
Contractual Principal Balance	0	101,000
Related Allowance	0	2,000
Average Recorded Investment	51,000	81,000
Interest Income Recognized	0	3,000
Impaired Financing Receivable with No Related Allowance | Commercial
Financing Receivable, Impaired [Line Items]
Recorded Investment	9,793,000	6,351,000
Contractual Principal Balance	11,941,000	8,387,000
Related Allowance	0	0
Average Recorded Investment	8,072,000	7,337,000
Interest Income Recognized	55,000	62,000
Impaired Financing Receivable with No Related Allowance | Real estate-construction
Financing Receivable, Impaired [Line Items]
Recorded Investment	4,957,000	6,289,000
Contractual Principal Balance	7,421,000	11,129,000
Related Allowance	0	0
Average Recorded Investment	5,623,000	5,657,000
Interest Income Recognized	5,000	2,000
Impaired Financing Receivable with No Related Allowance | Real estate-commercial
Financing Receivable, Impaired [Line Items]
Recorded Investment	13,121,000	14,999,000
Contractual Principal Balance	21,775,000	22,718,000
Related Allowance	0	0
Average Recorded Investment	14,060,000	18,306,000
Interest Income Recognized	35,000	249,000
Impaired Financing Receivable with No Related Allowance | Real estate-residential
Financing Receivable, Impaired [Line Items]
Recorded Investment	8,039,000	8,639,000
Contractual Principal Balance	9,264,000	9,580,000
Related Allowance	0	0
Average Recorded Investment	8,339,000	6,848,000
Interest Income Recognized	16,000	66,000
Impaired Financing Receivable with No Related Allowance | Installment
Financing Receivable, Impaired [Line Items]
Recorded Investment	492,000	485,000
Contractual Principal Balance	524,000	526,000
Related Allowance	0	0
Average Recorded Investment	489,000	356,000
Interest Income Recognized	1,000	5,000
Impaired Financing Receivable with No Related Allowance | Home equity
Financing Receivable, Impaired [Line Items]
Recorded Investment	2,016,000	2,073,000
Contractual Principal Balance	2,152,000	2,206,000
Related Allowance	0	0
Average Recorded Investment	2,044,000	2,337,000
Interest Income Recognized	$ 2,000	$ 10,000