STOCKHOLDERS' EQUITY (Details 6) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Unrealized gain (loss) on investment securities available-for-sale:
Unrealized gains (losses) on holding gains (losses) arising during period, before-tax amount	$ 8,174	$ 34,948
Less: reclassification adjustment for losses/(gains) included in income, before-tax amount	(5,577)	(483)
Net unrealized gain (loss), before-tax amount	2,597	34,465
Noncredit-related impairment loss on securities, before-tax amount		(5,066)
Unrealized gain (loss) on other asset investment, before-tax amount	17	17
Other comprehensive income, before-tax amount	2,614	29,416
Unrealized gain (loss) on investment securities available-for-sale:
Unrealized gains (losses) on holding gains (losses) arising during period, tax (expense) or benefit	(3,433)	(14,678)
Less: reclassification adjustment for losses/(gains) included in income, tax (expense) or benefit	2,342	203
Net unrealized gain (loss), tax (expense) or benefit	(1,091)	(14,475)
Noncredit-related impairment loss on securities, tax effect		2,128
Unrealized gain (loss) on other asset investment, tax (expense) or benefit	(7)	(7)
Other comprehensive income, tax (expense) or benefit	(1,098)	(12,354)
Unrealized gain on investment securities available-for-sale:
Unrealized gains (losses) on holding gains (losses) arising during period, net of tax amount	4,741	20,270
Less: reclassification adjustment for losses/(gains) included in income	(3,235)	(280)
Net unrealized gains (loss), net of tax amount	1,506	19,990
Noncredit-related impairment loss on securities, net of tax amount		(2,938)
Unrealized gain (loss) on other asset investment, net of tax amount	10	10
Other comprehensive income	$ 1,516	$ 17,062