FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS (Details 7) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Financial Assets:
Cash and cash equivalents	$ 1,039,885	$ 895,820		$ 1,323,106	$ 1,431,185
Short-term Investments	338,714	257,473
Securities purchased under resale agreements	1,225,000	1,300,000	[1]
Loans held for sale	45,950	204,970
Loans receivable, net	21,468,270	17,600,613
Investment in Federal Home Loan Bank stock	31,239	62,330
Investment in Federal Reserve Bank stock	54,451	48,333
Financial Liabilities:
Demand, savings and money market deposits	17,896,035	14,588,570
Time Deposits	6,112,739	5,824,348
Federal Home Loan Bank advances	317,241	315,092
Securities sold under repurchase agreements	795,000	995,000
Long-term debt	225,848	226,868
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Assets:
Cash and cash equivalents	1,039,885	895,820
Significant Other Observable Inputs (Level 2)
Financial Assets:
Short-term Investments	338,714	257,473
Securities purchased under resale agreements	1,191,060	1,279,406
Loans held for sale	45,950	212,469
Investment in Federal Home Loan Bank stock	31,239	62,330
Investment in Federal Reserve Bank stock	54,451	48,333
Accrued interest receivable	88,303	116,314
Financial Liabilities:
Demand, savings and money market deposits	17,896,035	14,588,570
Federal Home Loan Bank advances	336,302	308,521
Securities sold under repurchase agreements	870,434	1,134,774
Accrued interest payable	11,303	11,178
Long-term debt	205,777	184,415
Significant Unobservable Inputs (Level 3)
Financial Assets:
Loans receivable, net	20,997,379	16,741,674
Financial Liabilities:
Time Deposits	6,095,217	5,791,659
Carrying Amount
Financial Assets:
Cash and cash equivalents	1,039,885	895,820
Short-term Investments	338,714	257,473
Securities purchased under resale agreements	1,225,000	1,300,000
Loans held for sale	45,950	204,970
Loans receivable, net	21,468,270	17,600,613
Investment in Federal Home Loan Bank stock	31,239	62,330
Investment in Federal Reserve Bank stock	54,451	48,333
Accrued interest receivable	88,303	116,314
Financial Liabilities:
Demand, savings and money market deposits	17,896,035	14,588,570
Time Deposits	6,112,739	5,824,348
Federal Home Loan Bank advances	317,241	315,092
Securities sold under repurchase agreements	795,000	995,000
Accrued interest payable	11,303	11,178
Long-term debt	225,848	226,868
Fair Value Measurements
Financial Assets:
Cash and cash equivalents	1,039,885	895,820
Short-term Investments	338,714	257,473
Securities purchased under resale agreements	1,191,060	1,279,406
Loans held for sale	45,950	212,469
Loans receivable, net	20,997,379	16,741,674
Investment in Federal Home Loan Bank stock	31,239	62,330
Investment in Federal Reserve Bank stock	54,451	48,333
Accrued interest receivable	88,303	116,314
Financial Liabilities:
Demand, savings and money market deposits	17,896,035	14,588,570
Time Deposits	6,095,217	5,791,659
Federal Home Loan Bank advances	336,302	308,521
Securities sold under repurchase agreements	870,434	1,134,774
Accrued interest payable	11,303	11,178
Long-term debt	$ 205,777	$ 184,415

[1] Of the $1.40 billion resale agreements as of December 31, 2013, $100.0 million was recorded in cash and cash equivalents and $1.3 billion was recorded in securities under resale agreements in the consolidated balance sheet.