BUSINESS SEGMENTS (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Segment Reporting Information
Interest income	$ 238,423	$ 254,050
Charge for funds used	(38,783)	(43,089)
Interest spread on funds used	199,640	210,961
Interest expense	(29,132)	(35,132)
Credit on funds provided	38,783	43,089
Interest spread on funds provided	9,651	7,957
Net interest income	209,291	218,918
Provision for loan losses	4,327	18,100	65,184
Depreciation, amortization and accretion	14,997	38,669
Goodwill	337,438	337,438	337,438
Segment pre-tax profit (loss)	106,510	107,795
Segment assets	23,101,955	21,749,782	22,536,110
Retail Banking
Segment Reporting Information
Interest income	82,839	86,252
Charge for funds used	(19,983)	(22,260)
Interest spread on funds used	62,856	63,992
Interest expense	(12,644)	(15,548)
Credit on funds provided	32,395	35,040
Interest spread on funds provided	19,751	19,492
Net interest income	82,607	83,484
Provision for loan losses	3,680	6,914
Depreciation, amortization and accretion	2,420	11,933
Goodwill	320,566	320,566
Segment pre-tax profit (loss)	18,927	21,759
Segment assets	6,665,478	6,638,241
Commercial Banking
Segment Reporting Information
Interest income	140,060	142,966
Charge for funds used	(28,073)	(29,749)
Interest spread on funds used	111,987	113,217
Interest expense	(4,378)	(7,066)
Credit on funds provided	3,623	3,124
Interest spread on funds provided	(755)	(3,942)
Net interest income	111,232	109,275
Provision for loan losses	647	11,186
Depreciation, amortization and accretion	(2,819)	17,133
Goodwill	16,872	16,872
Segment pre-tax profit (loss)	66,681	60,428
Segment assets	10,464,086	10,079,411
Other
Segment Reporting Information
Interest income	15,524	24,832
Charge for funds used	9,273	8,920
Interest spread on funds used	24,797	33,752
Interest expense	(12,110)	(12,518)
Credit on funds provided	2,765	4,925
Interest spread on funds provided	(9,345)	(7,593)
Net interest income	15,452	26,159
Depreciation, amortization and accretion	15,396	9,603
Segment pre-tax profit (loss)	20,902	25,608
Segment assets	$ 5,972,391	$ 5,032,130