STOCKHOLDERS' EQUITY AND EARNINGS PER SHARE (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Unrealized gain on investment securities available-for-sale:
Unrealized gains on holding gains arising during period, before-tax amount	$ 73,910	$ (21,264)	$ 21,645
Less: reclassification adjustment for losses/(gains) included in income, before-tax amount	(757)	(9,703)	(31,237)
Net unrealized gain (loss), before-tax amount	73,153	(30,967)	(9,592)
Less: Noncredit-related impairment loss recorded in other comprehensive income	(5,066)	(5,103)	(15,458)
Foreign currency translation adjustments, before-tax amount	(1,552)	(1,317)	2,919
Unrealized gain (loss) on other asset investment, before-tax amount	53	334	(305)
Less: reclassification adjustment for gains (loss) included in income, before-tax amount	(23)	(61)
Other comprehensive income, before-tax amount	66,565	(37,114)	(22,436)
Unrealized gain on investment securities available-for-sale:
Unrealized gains on holding gains arising during period, tax (expense) or benefit	(31,042)	8,931	(9,091)
Less: reclassification adjustment for losses/(gains) included in income, tax (expense) or benefit	318	4,075	13,120
Net unrealized gain (loss), tax (expense) or benefit	(30,724)	13,006	4,029
Noncredit-related impairment loss on securities, tax effect	2,128	2,143	6,492
Foreign currency translation adjustments, tax (expense) or benefit	652	553	(1,226)
Unrealized gain (loss) on other asset investment, tax (expense) or benefit	(22)	(140)	128
Less: reclassification adjustment for gains (loss) included in income, tax (expense) or benefit	10	26
Other comprehensive income, tax (expense) or benefit	(27,956)	15,588	9,423
Unrealized gain on investment securities available-for-sale:
Unrealized gains on holding gains arising during period, net of tax amount	42,868	(12,333)	12,554
Less: reclassification adjustment for losses/(gains) included in income	(439)	(5,628)	(18,117)
Net unrealized gains (loss), net of tax amount	42,429	(17,961)	(5,563)
Noncredit-related impairment loss on securities	(2,938)	(2,960)	(8,966)
Foreign currency translation adjustments	(900)	(764)	1,693
Unrealized gain (loss) on other asset investment, net of tax amount	31	194	(177)
Less: reclassification adjustment for gains (loss) included in income, net of tax amount	(13)	(35)
Other comprehensive income (loss)	$ 38,609	$ (21,526)	$ (13,013)