FAIR VALUE MEASUREMENTS (Details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012
Activity for assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3)
Total gain (loss) on assets measured on a nonrecurring basis	$ (1,867,000)	$ (5,095,000)
Non-Covered other real estate owned
Activity for assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3)
Total gain (loss) on assets measured on a nonrecurring basis	(37,000)	(37,000)
Covered other real estate owned
Activity for assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3)
Total gain (loss) on assets measured on a nonrecurring basis	(2,461,000)	(3,442,000)
Non-covered impaired loans
Activity for assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3)
Total gain (loss) on assets measured on a nonrecurring basis	631,000	(1,617,000)
SBA loan servicing asset
Activity for assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3)
Total gain (loss) on assets measured on a nonrecurring basis		1,000
Covered private label CMOs
Activity for assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3)
Balance at the beginning of the period		45,149,000
Total realized in earnings		214,000
Total unrealized gain in comprehensive income		2,385,000
Net settlements		(3,695,000)
Balance at the end of the period	44,053,000	44,053,000
Other-than-temporary impairment loss		(1,100,000)
Measured on a Recurring Basis: | Total
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	1,351,701,000	1,351,701,000
Measured on a Recurring Basis: | Total | Government and government-sponsored entity residential mortgage-backed securities
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	1,084,595,000	1,084,595,000
Measured on a Recurring Basis: | Total | Covered private label CMOs
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	44,053,000	44,053,000
Measured on a Recurring Basis: | Total | Municipal securities
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	162,192,000	162,192,000
Measured on a Recurring Basis: | Total | Corporate securities
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	51,019,000	51,019,000
Measured on a Recurring Basis: | Total | Other securities
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	9,842,000	9,842,000
Measured on a Recurring Basis: | Level 1
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	8,068,000	8,068,000
Measured on a Recurring Basis: | Level 1 | Other securities
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	8,068,000	8,068,000
Measured on a Recurring Basis: | Level 2
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	1,299,580,000	1,299,580,000
Measured on a Recurring Basis: | Level 2 | Government and government-sponsored entity residential mortgage-backed securities
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	1,084,595,000	1,084,595,000
Measured on a Recurring Basis: | Level 2 | Municipal securities
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	162,192,000	162,192,000
Measured on a Recurring Basis: | Level 2 | Corporate securities
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	51,019,000	51,019,000
Measured on a Recurring Basis: | Level 2 | Other securities
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	1,774,000	1,774,000
Measured on a Recurring Basis: | Level 3
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	44,053,000	44,053,000
Measured on a Recurring Basis: | Level 3 | Covered private label CMOs
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	44,053,000	44,053,000
Measured on a Nonrecurring Basis: | Total
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	119,782,000	119,782,000
Measured on a Nonrecurring Basis: | Total | Non-Covered other real estate owned
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	552,000	552,000
Measured on a Nonrecurring Basis: | Total | Covered other real estate owned
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	17,194,000	17,194,000
Measured on a Nonrecurring Basis: | Total | Non-covered impaired loans
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	100,918,000	100,918,000
Measured on a Nonrecurring Basis: | Total | SBA loan servicing asset
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	1,118,000	1,118,000
Measured on a Nonrecurring Basis: | Level 2
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	30,843,000	30,843,000
Measured on a Nonrecurring Basis: | Level 2 | Non-Covered other real estate owned
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	552,000	552,000
Measured on a Nonrecurring Basis: | Level 2 | Covered other real estate owned
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	15,028,000	15,028,000
Measured on a Nonrecurring Basis: | Level 2 | Non-covered impaired loans
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	15,263,000	15,263,000
Measured on a Nonrecurring Basis: | Level 3
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	88,939,000	88,939,000
Measured on a Nonrecurring Basis: | Level 3 | Covered other real estate owned
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	2,166,000	2,166,000
Measured on a Nonrecurring Basis: | Level 3 | Non-covered impaired loans
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	85,655,000	85,655,000
Measured on a Nonrecurring Basis: | Level 3 | SBA loan servicing asset
Assets measured and recorded at fair value on a recurring and nonrecurring basis
Assets at fair value	$ 1,118,000	$ 1,118,000