Other assets by major categories (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]
Net deferred tax assets (net of valuation allowance)	$ 788,105	$ 812,819
Investments under the equity method	226,124	225,625
Bank Owned Life Insurance	0	0
Prepaid F D I C Insurance Assessment	359	360
Prepaid Taxes	186,173	198,120
Other prepaid expenses	82,926	83,719
Derivative Asset, Fair Value, Gross Asset	22,485	25,362
Trades receivables from brokers and counterparties	112,287	66,949	74,603
Others	366,832	233,489
Business Combination Contingent Consideration Asset	57,643	0
Total other assets	$ 1,842,934	$ 1,646,443