Other assets by major categories (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]
Net deferred tax assets (net of valuation allowance)	$ 773,994	$ 761,768
Investments under the equity method	219,021	197,006
Bank Owned Life Insurance	229,663	228,805
Prepaid F D I C Insurance Assessment	379	383
Prepaid Taxes	85,673	91,504
Other prepaid expenses	73,426	67,108
Derivative Asset, Fair Value, Gross Asset	28,996	34,710
Trades receivables from brokers and counterparties	74,603	71,680	144,171
Others	261,891	234,594
Total other assets	$ 1,747,646	$ 1,687,558