INVESTMENT SECURITIES (Details 5) (USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2014 item		Dec. 31, 2013 item
Schedule of Available-for-sale Securities
Fair value of available for sale securities	$ 2,529,652		$ 2,733,797
Number of securities in a continuous unrealized loss position for more than twelve months	168		65
Unrealized losses in loss position for twelve months or more	(22,713)		(19,729)
Number of individual securities with a continuous unrealized loss position less than 12 months	37		239
Unrealized losses in loss position for less than twelve months	(3,939)		(45,167)
Continuous unrealized loss position 12 months or more, fair value	966,358		250,361
U.S. Government agency and U.S. Government sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities
Schedule of Available-for-sale Securities
Fair value of available for sale securities	797,966		885,237
Total investment securities available-for-sale portfolio (as a percent)	32.00%		32.00%
Number of securities in a continuous unrealized loss position for more than twelve months	44		21
Unrealized losses in loss position for twelve months or more	(7,065)		(4,357)
Number of individual securities with a continuous unrealized loss position less than 12 months	22		55
Unrealized losses in loss position for less than twelve months	(1,992)		(10,570)
Continuous unrealized loss position 12 months or more, fair value	306,292		92,540
Municipal securities
Schedule of Available-for-sale Securities
Fair value of available for sale securities	289,479		280,979
Total investment securities available-for-sale portfolio (as a percent)	11.00%		10.00%
Number of securities in a continuous unrealized loss position for more than twelve months	79		32
Unrealized losses in loss position for twelve months or more	(4,632)		(6,768)
Number of individual securities with a continuous unrealized loss position less than 12 months	2		94
Unrealized losses in loss position for less than twelve months	(15)		(10,765)
Continuous unrealized loss position 12 months or more, fair value	138,062		47,892
Trust Preferred Securities
Schedule of Available-for-sale Securities
Number of securities in a continuous unrealized loss position for more than twelve months			5
Continuous unrealized loss position 12 months or more, fair value			14,400
Other securities
Schedule of Available-for-sale Securities
Fair value of available for sale securities	106,421		79,716
Number of securities in a continuous unrealized loss position for more than twelve months	1
Unrealized losses in loss position for twelve months or more	(64)
Number of individual securities with a continuous unrealized loss position less than 12 months	2		9
Unrealized losses in loss position for less than twelve months	(440)		(864)
Continuous unrealized loss position 12 months or more, fair value	2,904
Corporate debt securities | Investment grade
Schedule of Available-for-sale Securities
Fair value of available for sale securities	210,870		309,995
Number of securities in a continuous unrealized loss position for more than twelve months	6		4
Unrealized losses in loss position for twelve months or more	(1,389)		(1,806)
Number of individual securities with a continuous unrealized loss position less than 12 months	1		8
Unrealized losses in loss position for less than twelve months	(57)		(1,538)
Continuous unrealized loss position 12 months or more, fair value	89,752		79,442
Corporate debt securities | Non-investment grade
Schedule of Available-for-sale Securities
Fair value of available for sale securities	16,579	[1]	15,101	[1]
Number of securities in a continuous unrealized loss position for more than twelve months	4
Unrealized losses in loss position for twelve months or more	(3,505)		(5,629)
Continuous unrealized loss position 12 months or more, fair value	14,660		14,422
U.S. Treasury securities
Schedule of Available-for-sale Securities
Fair value of available for sale securities	449,312		491,632
Number of securities in a continuous unrealized loss position for more than twelve months	18
Unrealized losses in loss position for twelve months or more	(1,588)
Number of individual securities with a continuous unrealized loss position less than 12 months	3		33
Unrealized losses in loss position for less than twelve months	(40)		(3,622)
Continuous unrealized loss position 12 months or more, fair value	184,740
U.S. Government agency and U.S. Government sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities
Schedule of Available-for-sale Securities
Fair value of available for sale securities	111,757		178,870
Number of securities in a continuous unrealized loss position for more than twelve months	9		3
Unrealized losses in loss position for twelve months or more	(850)		(1,169)
Number of individual securities with a continuous unrealized loss position less than 12 months	5		19
Unrealized losses in loss position for less than twelve months	(513)		(3,280)
Continuous unrealized loss position 12 months or more, fair value	43,550		16,065
U.S. government agency and U.S. government sponsored enterprise debt securities
Schedule of Available-for-sale Securities
Fair value of available for sale securities	438,599		394,323
Total investment securities available-for-sale portfolio (as a percent)	17.00%		14.00%
Number of securities in a continuous unrealized loss position for more than twelve months	5
Unrealized losses in loss position for twelve months or more	(3,204)
Number of individual securities with a continuous unrealized loss position less than 12 months	2		16
Unrealized losses in loss position for less than twelve months	(882)		(12,726)
Continuous unrealized loss position 12 months or more, fair value	171,913
Other residential mortgage-backed securities: | Investment grade
Schedule of Available-for-sale Securities
Fair value of available for sale securities	57,206		46,327
Number of securities in a continuous unrealized loss position for more than twelve months	2
Unrealized losses in loss position for twelve months or more	(416)
Number of individual securities with a continuous unrealized loss position less than 12 months			5
Unrealized losses in loss position for less than twelve months			(1,802)
Continuous unrealized loss position 12 months or more, fair value	14,485
Other commercial mortgage-backed securities: | Investment grade
Schedule of Available-for-sale Securities
Fair value of available for sale securities	$ 51,463		$ 51,617

[1] For the six months ended June 30, 2014 and the year ended December 31, 2013, the Company did not record any OTTI.