FAIR VALUE (Details 6) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012 Carrying Amount or Notional Amount	Dec. 31, 2011 Carrying Amount or Notional Amount	Dec. 31, 2012 Estimated Fair Value	Dec. 31, 2011 Estimated Fair Value
Financial Assets
Cash and cash equivalents		$ 1,323,106	$ 1,431,185	$ 1,323,106	$ 1,431,185
Short-term investments		366,378	61,834	366,378	61,834
Securities purchased under resale agreements		1,450,000	786,434	1,442,302	791,745
Investment securities available-for-sale		2,607,029	3,072,578	2,607,029	3,072,578
Loans held for sale		174,317	278,603	180,349	285,181
Loans receivable, net		14,645,785	13,984,930	14,743,218	13,520,712
Investment in Federal Home Loan Bank stock		107,275	136,897	107,275	136,897
Investment in Federal Reserve Bank stock		48,003	47,512	48,003	47,512
Accrued interest receivable		94,837	89,686	94,837	89,686
Equity swap agreements			22,709		202
Foreign exchange options		85,614	85,614	5,011	3,899
Interest rate swaps		1,190,793	585,196	36,943	20,474
Short-term foreign exchange contracts		112,459	210,295	896	1,403
Financial Liabilities
Demand, savings and money market deposits		12,187,740	10,307,001	12,187,740	10,307,001
Time deposits		6,121,614	7,146,001	6,115,530	7,194,125
Federal Home Loan Bank advances		312,975	455,251	333,060	479,029
Securities sold under repurchase agreements		995,000	1,020,208	1,173,830	1,177,331
Other borrowings	20,000	20,000		20,000
Accrued interest payable		10,855	15,447	10,855	15,447
Long-term debt		137,178	212,178	83,762	144,392
Derivatives liabilities		$ 1,392,494	$ 835,913	$ 42,060	$ 24,164
Maximum term of maturity for securities purchased under resale agreements to be included in cash and cash equivalents	90 days
Term of maturity that securities purchased under resale agreements must exceed to be included in certain fair value calculations	90 days
Maximum term of maturity for carrying amount of securities sold under repurchase agreements to approximate fair value	90 days