BUSINESS SEGMENTS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Segment Reporting Information [Line Items]
Interest income	$ 282,741	$ 231,400	$ 811,544	$ 803,636
Charge for funds used	(53,712)	(54,022)	(180,442)	(186,791)
Interest spread on funds used	229,029	177,378	631,102	616,845
Interest expense	(44,959)	(48,595)	(137,592)	(155,484)
Credit on funds provided	53,712	54,022	180,442	186,791
Interest spread on funds provided	8,753	5,427	42,850	31,307
Net interest income before provision for loan losses	237,782	182,805	673,952	648,152
Provision for loan losses	(22,000)	(38,648)	(75,006)	(170,325)	(200,159)
Depreciation, amortization and accretion	(16,670)	(68,294)	(100,082)	(147,113)
Goodwill	337,438	337,438	337,438	337,438	337,438
Segment pre-tax profit	97,685	73,527	279,995	170,203
Segment assets	21,813,046	20,417,246	21,813,046	20,417,246	20,700,537
Number of operating segments	3		3
Number of core segments	2		2
Retail Banking [Member]
Segment Reporting Information [Line Items]
Interest income	88,189	69,311	270,943	269,453
Charge for funds used	(22,394)	(29,159)	(72,073)	(87,078)
Interest spread on funds used	65,795	40,152	198,870	182,375
Interest expense	(21,407)	(26,851)	(67,515)	(89,422)
Credit on funds provided	46,480	48,391	158,212	161,796
Interest spread on funds provided	25,073	21,540	90,697	72,374
Net interest income before provision for loan losses	90,868	61,692	289,567	254,749
Provision for loan losses	(11,185)	(26,261)	(20,128)	(59,976)
Depreciation, amortization and accretion	(6,815)	(19,282)	(34,941)	(50,669)
Goodwill	320,566	320,566	320,566	320,566
Segment pre-tax profit	15,773	(18,021)	81,443	(1,172)
Segment assets	6,230,680	6,450,883	6,230,680	6,450,883
Commercial Lending [Member]
Segment Reporting Information [Line Items]
Interest income	166,789	143,729	465,138	473,004
Charge for funds used	(33,575)	(46,446)	(111,128)	(111,119)
Interest spread on funds used	133,214	97,283	354,010	361,885
Interest expense	(9,248)	(5,885)	(23,236)	(19,015)
Credit on funds provided	3,291	2,431	10,225	11,738
Interest spread on funds provided	(5,957)	(3,454)	(13,011)	(7,277)
Net interest income before provision for loan losses	127,257	93,829	340,999	354,608
Provision for loan losses	(10,815)	(12,387)	(54,878)	(110,349)
Depreciation, amortization and accretion	(2,912)	(46,469)	(51,012)	(91,081)
Goodwill	16,872	16,872	16,872	16,872
Segment pre-tax profit	64,290	64,698	164,258	106,165
Segment assets	10,345,990	9,728,305	10,345,990	9,728,305
Other [Member]
Segment Reporting Information [Line Items]
Interest income	27,763	18,360	75,463	61,179
Charge for funds used	2,257	21,583	2,759	11,406
Interest spread on funds used	30,020	39,943	78,222	72,585
Interest expense	(14,304)	(15,859)	(46,841)	(47,047)
Credit on funds provided	3,941	3,200	12,005	13,257
Interest spread on funds provided	(10,363)	(12,659)	(34,836)	(33,790)
Net interest income before provision for loan losses	19,657	27,284	43,386	38,795
Provision for loan losses	0	0	0	0
Depreciation, amortization and accretion	(6,943)	(2,543)	(14,129)	(5,363)
Goodwill	0	0	0	0
Segment pre-tax profit	17,622	26,850	34,294	65,210
Segment assets	$ 5,236,376	$ 4,238,058	$ 5,236,376	$ 4,238,058