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Impairment of Investment Securities - Pooled Trust Preferred Collateralized Debt Obligations (Detail) (USD $) In Thousands, unless otherwise specified			3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Pooled Trust Preferred Collateralized Debt Obligations [Member]	Mar. 31, 2014 Pooled Trust Preferred Collateralized Debt Obligations [Member] Mezzanine [Member] Pre TSL IV [Member] Bank	Mar. 31, 2014 Pooled Trust Preferred Collateralized Debt Obligations [Member] Mezzanine [Member] Pre TSL V [Member] Bank	Mar. 31, 2014 Pooled Trust Preferred Collateralized Debt Obligations [Member] Mezzanine [Member] Pre TSL VII [Member] Bank	Mar. 31, 2014 Pooled Trust Preferred Collateralized Debt Obligations [Member] Mezzanine [Member] Pre TSL VIII [Member] Bank	Mar. 31, 2014 Pooled Trust Preferred Collateralized Debt Obligations [Member] Mezzanine [Member] Pre TSL IX [Member] Bank	Mar. 31, 2014 Pooled Trust Preferred Collateralized Debt Obligations [Member] Mezzanine [Member] Pre TSL X [Member] Bank	Mar. 31, 2014 Pooled Trust Preferred Collateralized Debt Obligations [Member] Mezzanine [Member] Pre TSL XII [Member] Bank	Mar. 31, 2014 Pooled Trust Preferred Collateralized Debt Obligations [Member] Mezzanine [Member] Pre TSL XIII [Member] Bank	Mar. 31, 2014 Pooled Trust Preferred Collateralized Debt Obligations [Member] Mezzanine [Member] Pre TSL XIV [Member] Bank	Mar. 31, 2014 Pooled Trust Preferred Collateralized Debt Obligations [Member] Mezzanine [Member] MMCap I [Member] Bank
Impairment Of Investment Securities [Line Items]
Book Value			$ 42,214	$ 1,830	$ 58	$ 2,636	$ 1,985	$ 2,313	$ 1,409	$ 5,410	$ 12,408	$ 13,720	$ 445
Securities available for sale, at fair value	1,351,039	1,318,365	27,876	1,297	28	2,609	1,400	1,390	1,391	3,311	7,941	8,146	363
Unrealized Gain (Loss)			$ (14,338)	$ (533)	$ (30)	$ (27)	$ (585)	$ (923)	$ (18)	$ (2,099)	$ (4,467)	$ (5,574)	$ (82)
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 (in banks)				6	3	14	30	42	46	68	61	58	11
Deferrals and Defaults as a % of Current Collateral				18.05%	100.00%	54.14%	54.77%	28.05%	35.07%	30.28%	27.78%	31.90%	58.76%
Excess Subordination as a % of Current Performing Collateral				55.72%	0.00%	0.00%	0.00%	7.86%	0.00%	0.00%	19.84%	50.44%	14.63%

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Available for sale securities book value.

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Pooled trust preferred collateralized debt obligations in number of banks.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558



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-Publisher FASB

-Name Accounting Standards Codification

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-Section 50

-Paragraph 5

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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563



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-Publisher FASB

-Name Accounting Standards Codification

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-Section 45

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-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

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Amount of unrealized gain (loss) on investments in debt and equity securities classified as available-for-sale securities.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563

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Description of the credit rating indicative of likelihood of repayment of the debt instrument given by a credit rating agency (for example, Standard and Poor's, Moody's, Fitch).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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