STOCKHOLDERS' EQUITY (Details 6) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Unrealized gain on investment securities available-for-sale:
Unrealized gains on holding gains arising during period, before-tax amount	$ 1,728	$ 26,148	$ 36,676	$ 38,911
Less: reclassification adjustment for losses/(gains) included in income, before-tax amount	(71)	(1,117)	(554)	(3,632)
Net unrealized gains, before-tax amount	1,657	25,031	36,122	35,279
Noncredit-related impairment loss on securities, before tax			(5,066)	(5,091)	(5,100)
Foreign currency translation adjustments, before-tax amount	(10)	116	7	(1,147)
Other comprehensive income, before-tax amount	1,647	25,147	31,063	29,041
Unrealized gain on investment securities available-for-sale:
Unrealized gains on holding gains arising during period, tax (expense) or benefit	(726)	(10,982)	(15,404)	(16,342)
Less: reclassification adjustment for losses/(gains) included in income, tax (expense) or benefit	30	469	233	1,526
Net unrealized gains, tax (expense) or benefit	(696)	(10,513)	(15,171)	(14,816)
Noncredit-related impairment loss on securities, tax effect			2,128	2,138
Foreign currency translation adjustments, tax (expense) or benefit	4	(49)	(3)	482
Other comprehensive income, tax (expense) or benefit	(692)	(10,562)	(13,046)	(12,196)
Unrealized gain on investment securities available-for-sale:
Unrealized gains on holding gains arising during period, net of tax amount	1,002	15,166	21,272	22,569
Less: reclassification adjustment for losses/(gains) included in income	(41)	(648)	(321)	(2,107)
Net unrealized gains, net of tax amount	961	14,518	20,951	20,462
Noncredit-related impairment loss on securities, net of tax amount			(2,938)	(2,953)
Foreign currency translation adjustments, net of tax amount	(6)	67	4	(665)
Other comprehensive income	$ 955	$ 14,585	$ 18,017	$ 16,844