Impairment of Investment Securities - Pooled Trust Preferred Collateralized Debt Obligations (Detail) (USD $) In Thousands, unless otherwise specified				12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Mezzanine [Member]	Dec. 31, 2013 Mezzanine [Member] Pre TSL IV [Member] Bank	Dec. 31, 2013 Mezzanine [Member] Pre TSL V [Member] Bank	Dec. 31, 2013 Mezzanine [Member] Pre TSL VII [Member] Bank	Dec. 31, 2013 Mezzanine [Member] Pre TSL VIII [Member] Bank	Dec. 31, 2013 Mezzanine [Member] Pre TSL IX [Member] Bank	Dec. 31, 2013 Mezzanine [Member] Pre TSL X [Member] Bank	Dec. 31, 2013 Mezzanine [Member] Pre TSL XII [Member] Bank	Dec. 31, 2013 Mezzanine [Member] Pre TSL XIII [Member] Bank	Dec. 31, 2013 Mezzanine [Member] Pre TSL XIV [Member] Bank	Dec. 31, 2013 Mezzanine [Member] MMCap I [Member] Bank	Dec. 31, 2013 Maximum [Member]
Impairment Of Investment Securities [Line Items]
Available for sale securities book value	$ 42,040			$ 1,830	$ 57	$ 2,581	$ 1,956	$ 2,304	$ 1,388	$ 5,374	$ 12,452	$ 13,653	$ 445
Fair Value	1,318,365	1,171,303	23,523	1,264	34	2,367	1,100	1,173	1,291	2,852	6,862	6,234	346
Unrealized Gain (Loss)	$ (18,517)			$ (566)	$ (23)	$ (214)	$ (856)	$ (1,131)	$ (97)	$ (2,522)	$ (5,590)	$ (7,419)	$ (99)
Debt Instrument, Credit Rating				B1/B	C/-	Ca/C	C/C	Caa1/C	Caa3/C	Caa3/C	Caa3/C	Ca/C	Ca/C
Number of Banks				6	3	14	30	42	46	68	61	59	11
Deferrals and Defaults as a % of Current Collateral				18.05%	100.00%	54.14%	58.01%	30.29%	35.07%	30.26%	31.09%	37.00%	58.76%
Excess Subordination as a % of Current Performing Collateral				58.54%	0.00%	0.00%	0.00%	3.36%	0.00%	0.00%	16.78%	42.17%	10.41%	59.00%

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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