INVESTMENT SECURITIES (Details 4) (USD $)					3 Months Ended							6 Months Ended
	Jun. 30, 2012 item	Dec. 31, 2011	Jun. 30, 2012 US Government Agencies and Government Sponsored Enterprise Debt Securities item	Jun. 30, 2012 Residential mortgage-backed securities item	Jun. 30, 2012 Corporate debt securities	Jun. 30, 2012 Corporate debt securities Investment grade item	Dec. 31, 2011 Corporate debt securities Investment grade	Jun. 30, 2012 Corporate debt securities Non-investment grade		Dec. 31, 2011 Corporate debt securities Non-investment grade		Jun. 30, 2012 Trust Preferred Securities item	Jun. 30, 2012 U.S. Treasury securities item	Dec. 31, 2011 U.S. Treasury securities	Jun. 30, 2012 Municipal securities item	Dec. 31, 2011 Municipal securities
Schedule of Available-for-sale Securities
Fair value of available for sale securities	$ 1,873,739,000	$ 3,072,578,000				$ 426,055,000	$ 1,322,561,000	$ 14,919,000	[1]	$ 19,615,000	[1]		$ 72,188,000	$ 20,725,000	$ 65,782,000	$ 79,946,000
Continuous unrealized loss position 12 months or more, fair value	328,479,000	359,776,000				318,122,000	350,181,000	10,357,000		9,595,000		10,400,000
Total investment securities available-for-sale portfolio (as a percent)						23.00%						1.00%
Number of securities in a continuous unrealized loss position for more than twelve months	20					15						5
Number of individual securities with a continuous unrealized loss position less than 12 months	34		6	18		6							3		1
Percentage of total amortized cost basis of these securities								49.00%
Gross Unrealized Losses	(57,743,000)	(107,746,000)				(47,377,000)	(95,610,000)	(9,778,000)	[1]	(11,078,000)	[1]		(25,000)		(30,000)	(5,000)
Gross unrealized losses in loss position twelve months or more	41,656,000	44,188,000				31,878,000	33,675,000	9,778,000		10,513,000
Gross unrealized losses, trust preferred securities, portion representing impairment loss on securities not other-than-temporarily-impaired								4,700,000
Gross unrealized losses, trust preferred securities, portion representing non-credit impairment loss on securities other-than-temporarily-impaired								5,100,000
Impairment loss relating to additional increases to the amount related to the credit loss for which an other-than-temporary impairment was previously recognized												99,000
Decrease in corporate debt securities					663,600,000
Scheduled maturities of investment securities available-for sale, amortized cost basis
Due within one year	360,410,000
Due after one year through five years	150,822,000
Due after five years through ten years	519,207,000
Due after ten years	872,350,000
Total investment securities available-for-sale	1,902,789,000
Scheduled maturities of investment securities available-for sale, fair value
Due within one year	356,383,000
Due after one year through five years	149,545,000
Due after five years through ten years	480,635,000
Due after ten years	887,176,000
Total investment securities available-for-sale	$ 1,873,739,000

[1] For the six months ended June 30, 2012, the Company recorded $99 thousand, on a pre-tax basis, of the credit portion of OTTI through earnings and $5.1 million of the non-credit portion of OTTI for pooled trust preferred securities in other comprehensive income. The Company recorded $633 thousand, on a pre-tax basis, of the credit portion of OTTI through earnings and $5.1 million of the non-credit portion of OTTI for pooled trust preferred securities and other mortgage-backed securities in other comprehensive income for the year ended December 31, 2011.