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Period Type:	duration

Number of non-agency residential mortgage-backed securities that had unrealized losses.

+ References

No definition available.

+ Details

Name:	susq_NonAgencyResidentialMortgageBackedSecuritiesNumberOfSecurities
Namespace Prefix:	susq_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of non-agency residential mortgage-backed securities that have subprime or Alt-A components.

+ References

No definition available.

+ Details

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Namespace Prefix:	susq_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of non-agency residential mortgage-backed securities determined to be other than temporarily impaired.

+ References

No definition available.

+ Details

Name:	susq_NonAgencyResidentialMortgageBackedSecuritiesNumberOfSecuritiesDeterminedToBeOtherThanTemporarilyImpaired
Namespace Prefix:	susq_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of non-agency residential mortgage-backed securities that were rated below investment grade.

+ References

No definition available.

+ Details

Name:	susq_NonAgencyResidentialMortgageBackedSecuritiesNumberOfSecuritiesRatedBelowInvestmentGrade
Namespace Prefix:	susq_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of days mortgage is past due related to the conditional default rate.

+ References

No definition available.

+ Details

Name:	susq_NumberOfDaysMortgageIsPastDueRelatedToCumulativeDefaultRate
Namespace Prefix:	susq_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying value of securities pledged to secure public funds and for other purposes as required by law.

+ References

No definition available.

+ Details

Name:	susq_SecuritiesPledgedToSecurePublicFunds
Namespace Prefix:	susq_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of aggregate unrealized losses relating to pooled trust preferred securities.

+ References

No definition available.

+ Details

Name:	susq_UnrealizedLossPooledTrustPreferredSecurities
Namespace Prefix:	susq_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Accumulated other comprehensive loss related to portion of other than temporary impairment (OTTI) due to factors other than credit losses on debt securities categorized as available-for-sale that an entity does not intend to sell and which it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis of the debt security. The amount represented by this item is net of tax, as applicable.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 14A

-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669686-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (aaa)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Investment Securities (Narrative) (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014 Securities	Dec. 31, 2013	Sep. 30, 2013
Investment [Line Items]
Amount of securities pledged to secure public funds and other purposes as required by law	$ 1,432,660	$ 1,512,824
Number of non-agency residential mortgage-backed securities that had unrealized losses	1
Number of non-agency residential mortgage-backed securities rated below investment grade	0
Number of non-agency residential mortgage-backed securities that have subprime or Alt-A components	0
Number of non-agency residential-mortgage backed securities with other-than-temporary impairment	0
Accumulated other comprehensive income (loss), other-than- temporarily impaired securities			321
Minimum [Member]
Investment [Line Items]
Number of days mortgage is past due related to cumulative default rate	60 days
Maximum [Member]
Investment [Line Items]
Number of days mortgage is past due related to cumulative default rate	90 days
Other Structured Financial Products [Member]
Investment [Line Items]
Unrealized loss	$ 12,801		$ 13,605