INVESTMENT SECURITIES (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Continuous unrealized loss position, fair values of investment securities available-for-sale [Abstract]
Continuous unrealized loss position less than 12 months, fair value	$ 1,108,347	$ 1,692,885
Continuous unrealized loss position less than 12 months, unrealized losses	(63,558)	(29,417)
Continuous unrealized loss position 12 months or more, fair value	359,776	16,180
Continuous unrealized loss position 12 months or more, unrealized losses	(44,188)	(19,435)
Continuous unrealized loss position total, fair value	1,468,123	1,709,065
Continuous unrealized loss position total, unrealized losses	(107,746)	(48,852)
U.S. Government agency and U.S. Government sponsored enterprise debt securities
Continuous unrealized loss position, fair values of investment securities available-for-sale [Abstract]
Continuous unrealized loss position less than 12 months, fair value	143,265	935,654
Continuous unrealized loss position less than 12 months, unrealized losses	(279)	(18,121)
Continuous unrealized loss position total, fair value	143,265	935,654
Continuous unrealized loss position total, unrealized losses	(279)	(18,121)
U.S. Government agency and U.S. Government sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities
Continuous unrealized loss position, fair values of investment securities available-for-sale [Abstract]
Continuous unrealized loss position less than 12 months, fair value	195,393
Continuous unrealized loss position less than 12 months, unrealized losses	(772)
Continuous unrealized loss position total, fair value	195,393
Continuous unrealized loss position total, unrealized losses	(772)
Municipal securities
Continuous unrealized loss position, fair values of investment securities available-for-sale [Abstract]
Continuous unrealized loss position less than 12 months, fair value	1,158
Continuous unrealized loss position less than 12 months, unrealized losses	(5)
Continuous unrealized loss position total, fair value	1,158
Continuous unrealized loss position total, unrealized losses	(5)
Other residential mortgage-backed securities: | Non-investment grade
Continuous unrealized loss position, fair values of investment securities available-for-sale [Abstract]
Continuous unrealized loss position 12 months or more, fair value		6,254
Continuous unrealized loss position 12 months or more, unrealized losses		(8,742)
Continuous unrealized loss position total, fair value		6,254
Continuous unrealized loss position total, unrealized losses		(8,742)
Corporate debt securities | Investment grade
Continuous unrealized loss position, fair values of investment securities available-for-sale [Abstract]
Continuous unrealized loss position less than 12 months, fair value	754,055	656,434
Continuous unrealized loss position less than 12 months, unrealized losses	(61,935)	(8,765)
Continuous unrealized loss position 12 months or more, fair value	350,181
Continuous unrealized loss position 12 months or more, unrealized losses	(33,675)
Continuous unrealized loss position total, fair value	1,104,236	656,434
Continuous unrealized loss position total, unrealized losses	(95,610)	(8,765)
Corporate debt securities | Non-investment grade
Continuous unrealized loss position, fair values of investment securities available-for-sale [Abstract]
Continuous unrealized loss position less than 12 months, fair value	9,973	24,105
Continuous unrealized loss position less than 12 months, unrealized losses	(565)	(623)
Continuous unrealized loss position 12 months or more, fair value	9,595	9,926
Continuous unrealized loss position 12 months or more, unrealized losses	(10,513)	(10,693)
Continuous unrealized loss position total, fair value	19,568	34,031
Continuous unrealized loss position total, unrealized losses	(11,078)	(11,316)
Other securities
Continuous unrealized loss position, fair values of investment securities available-for-sale [Abstract]
Continuous unrealized loss position less than 12 months, fair value	4,503	76,692
Continuous unrealized loss position less than 12 months, unrealized losses	(2)	(1,908)
Continuous unrealized loss position total, fair value	4,503	76,692
Continuous unrealized loss position total, unrealized losses	$ (2)	$ (1,908)