ALLOWANCE FOR LOAN AND LEASE LOSSES - Changes in the Allowance for Loan and Lease Losses (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended					6 Months Ended			12 Months Ended			6 Months Ended	12 Months Ended			6 Months Ended	12 Months Ended			6 Months Ended	12 Months Ended			6 Months Ended	12 Months Ended			6 Months Ended	12 Months Ended			6 Months Ended	12 Months Ended			6 Months Ended	12 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 Non Covered Loans	Dec. 31, 2011 Non Covered Loans	Jun. 30, 2012 Commercial	Dec. 31, 2011 Commercial	Jun. 30, 2012 Commercial Non Covered Loans	Dec. 31, 2011 Commercial Non Covered Loans	Jun. 30, 2012 Real estate-construction	Dec. 31, 2011 Real estate-construction	Jun. 30, 2012 Real estate-construction Non Covered Loans	Dec. 31, 2011 Real estate-construction Non Covered Loans	Jun. 30, 2012 Real estate-commercial	Dec. 31, 2011 Real estate-commercial	Jun. 30, 2012 Real estate-commercial Non Covered Loans	Dec. 31, 2011 Real estate-commercial Non Covered Loans	Jun. 30, 2012 Real estate-residential	Dec. 31, 2011 Real estate-residential	Jun. 30, 2012 Real estate-residential Non Covered Loans	Dec. 31, 2011 Real estate-residential Non Covered Loans	Jun. 30, 2012 Installment	Dec. 31, 2011 Installment	Jun. 30, 2012 Installment Non Covered Loans	Dec. 31, 2011 Installment Non Covered Loans	Jun. 30, 2012 Home equity	Dec. 31, 2011 Home equity	Jun. 30, 2012 Home equity Non Covered Loans	Dec. 31, 2011 Home equity Non Covered Loans	Jun. 30, 2012 All other	Dec. 31, 2011 All other	Jun. 30, 2012 All other Non Covered Loans	Dec. 31, 2011 All other Non Covered Loans
Allowance for loan and lease losses:
Balance at beginning of period	$ 49,437	$ 52,576	$ 54,537	$ 53,671	$ 53,645	$ 52,576	$ 57,235	$ 52,576	$ 57,235			$ 10,289	$ 10,138			$ 4,424	$ 8,326			$ 18,228	$ 14,917			$ 4,994	$ 8,907			$ 1,659	$ 1,981			$ 10,751	$ 10,939			$ 2,231	$ 2,027
Provision for loan and lease losses	8,364	3,258	5,164	7,643	5,756	11,622	6,403	11,622	19,210			1,263	2,825			544	2,345			6,966	13,384			1,271	(2,407)			(510)	(159)			1,847	1,878			241	1,344
Gross charge-offs	7,138	6,822	7,791	7,174	6,232	13,960	10,833	13,960	25,798			2,315	3,436			2,504	6,279			6,055	10,382			795	1,551			176	526			1,559	2,183			556	1,441
Recoveries	289	425	666	397	502	714	866	714	1,929			120	762			0	32			181	309			37	45			198	363			52	117			126	301
Total net charge-offs								13,246	23,869			2,195	2,674			2,504	6,247			5,874	10,073			758	1,506			(22)	163			1,507	2,066			430	1,140
Balance at end of period	50,952	49,437	52,576	54,537	53,671	50,952	53,671	50,952	52,576			9,357	10,289			2,464	4,424			19,320	18,228			5,507	4,994			1,171	1,659			11,091	10,751			2,042	2,231
Ending allowance on loans individually evaluated for impairment								13,501	12,539			3,179	3,205			1,261	2,578			8,764	6,441			295	313			0	0			2	2			0	0
Ending allowance on loans collectively evaluated for impairment								37,451	40,037			6,178	7,084			1,203	1,846			10,556	11,787			5,212	4,681			1,171	1,659			11,089	10,749			2,042	2,231
Impaired Financing Receivable, Related Allowance								50,952	52,576			9,357	10,289			2,464	4,424			19,320	18,228			5,507	4,994			1,171	1,659			11,091	10,751			2,042	2,231
Loans and Leases:
Ending balance of loans individually evaluated for impairment								66,740	60,277			16,326	8,351			8,318	17,387			39,075	30,708			2,920	3,730			0	0			101	101			0	0
Ending balance of loans collectively evaluated for impairment								2,945,870	2,908,170			807,564	848,630			77,855	97,587			1,282,371	1,202,359			289,583	284,250			61,590	67,543			365,312	358,859			61,595	48,942
Total loans, excluding covered loans	$ 3,012,610		$ 2,968,447			$ 3,012,610		$ 3,012,610	$ 2,968,447	$ 823,890	$ 856,981	$ 823,890	$ 856,981	$ 86,173	$ 114,974	$ 86,173	$ 114,974	$ 1,321,446	$ 1,233,067	$ 1,321,446	$ 1,233,067	$ 292,503	$ 287,980	$ 292,503	$ 287,980	$ 61,590	$ 67,543	$ 61,590	$ 67,543	$ 365,413	$ 358,960	$ 365,413	$ 358,960	$ 61,595	$ 48,942	$ 61,595	$ 48,942