FAIR VALUE (Details 7) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Financial Assets
Federal funds sold	$ 30,000
Estimated Fair Value
Financial Assets
Cash and cash equivalents	1,635,854	1,431,185
Short-term investments	177,576	61,834
Federal funds sold	30,000
Securities purchased under resale agreements	646,041	791,745
Loans Held for sale	289,989	285,181
Loans receivable, net	13,310,866	13,520,712
Investment in Federal Home Loan Bank stock	130,506	136,897
Investment in Federal Reserve Bank stock	47,639	47,512
Accrued interest receivable	95,337	89,686
Financial Liabilities
Demand, savings and money market deposits	10,563,249	10,307,001
Time deposits	6,821,016	7,194,125
Federal Home Loan Bank advances	420,758	479,029
Securities sold under repurchase agreements	1,172,723	1,177,331
Accrued interest payable	16,439	15,447
Long-term debt	139,361	144,392
Level 1
Financial Assets
Cash and cash equivalents	1,635,854	1,431,185
Level 2
Financial Assets
Short-term investments	177,576	61,834
Federal funds sold	30,000
Securities purchased under resale agreements	646,041	791,745
Loans Held for sale	289,989	285,181
Investment in Federal Home Loan Bank stock	130,506	136,897
Investment in Federal Reserve Bank stock	47,639	47,512
Accrued interest receivable	95,337	89,686
Financial Liabilities
Demand, savings and money market deposits	10,563,249	10,307,001
Federal Home Loan Bank advances	420,758	479,029
Securities sold under repurchase agreements	1,172,723	1,177,331
Accrued interest payable	16,439	15,447
Long-term debt	139,361	144,392
Level 3
Financial Assets
Loans receivable, net	13,310,866	13,520,712
Financial Liabilities
Time deposits	$ 6,821,016	$ 7,194,125