Loans And Leases (Allowance For Credit Losses And Recorded Investment In Financing Receivables) (Details) (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2011	Dec. 31, 2010
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 189,292	$ 191,834
Charge-offs	(27,427)	(105,024)
Recoveries	4,095	16,150
Provision	25,000	88,000
Ending balance	190,960	190,960
Ending balance: Individually evaluated for impairment	17,608	17,608
Ending balance: Collectively evaluated for impairment	173,352	173,352
Financing receivables: Ending Balance	9,702,669	9,702,669	9,633,197
Financing receivables: Individually evaluated for impairment: Ending balance	169,651	169,651
Financing receivables: Collectively evaluated for impairment: Ending balance	9,533,018	9,533,018
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	29,358	31,608
Charge-offs	(6,445)	(21,386)
Recoveries	1,123	3,226
Provision	4,557	15,145
Ending balance	28,593	28,593
Ending balance: Individually evaluated for impairment	3,064	3,064
Ending balance: Collectively evaluated for impairment	25,528	25,528
Financing receivables: Ending Balance	1,810,664	1,810,664
Financing receivables: Individually evaluated for impairment: Ending balance	18,041	18,041
Financing receivables: Collectively evaluated for impairment: Ending balance	1,792,623	1,792,623
Real Estate - Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	44,432	50,250
Charge-offs	(7,227)	(27,189)
Recoveries	738	6,194
Provision	3,015	11,703
Ending balance	40,958	40,958
Ending balance: Individually evaluated for impairment	1,478	1,478
Ending balance: Collectively evaluated for impairment	39,481	39,481
Financing receivables: Ending Balance	771,734	771,734
Financing receivables: Individually evaluated for impairment: Ending balance	37,296	37,296
Financing receivables: Collectively evaluated for impairment: Ending balance	734,438	734,438
Real Estate Secured - Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	29,990	28,320
Charge-offs	(5,476)	(15,604)
Recoveries	214	1,497
Provision	4,991	15,506
Ending balance	29,719	29,719
Ending balance: Individually evaluated for impairment	2,550	2,550
Ending balance: Collectively evaluated for impairment	27,169	27,169
Financing receivables: Ending Balance	2,728,934	2,728,934
Financing receivables: Individually evaluated for impairment: Ending balance	27,836	27,836
Financing receivables: Collectively evaluated for impairment: Ending balance	2,701,098	2,701,098
Real Estate Secured - Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	72,554	70,137
Charge-offs	(6,712)	(33,446)
Recoveries	1,100	2,925
Provision	11,072	38,398
Ending balance	78,014	78,014
Ending balance: Individually evaluated for impairment	10,368	10,368
Ending balance: Collectively evaluated for impairment	67,646	67,646
Financing receivables: Ending Balance	3,013,787	3,013,787
Financing receivables: Individually evaluated for impairment: Ending balance	86,330	86,330
Financing receivables: Collectively evaluated for impairment: Ending balance	2,927,457	2,927,457
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	2,755	2,841
Charge-offs	(483)	(3,175)
Recoveries	582	1,128
Provision	634	2,694
Ending balance	3,488	3,488
Ending balance: Individually evaluated for impairment	148	148
Ending balance: Collectively evaluated for impairment	3,340	3,340
Financing receivables: Ending Balance	698,804	698,804
Financing receivables: Individually evaluated for impairment: Ending balance	148	148
Financing receivables: Collectively evaluated for impairment: Ending balance	698,656	698,656
Leases [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	10,091	8,643
Charge-offs	(1,084)	(4,224)
Recoveries	338	1,180
Provision	774	4,520
Ending balance	10,119	10,119
Ending balance: Individually evaluated for impairment	0	0
Ending balance: Collectively evaluated for impairment	10,119	10,119
Financing receivables: Ending Balance	678,746	678,746
Financing receivables: Individually evaluated for impairment: Ending balance	0	0
Financing receivables: Collectively evaluated for impairment: Ending balance	678,746	678,746
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	112	35
Provision	(43)	34
Ending balance	69	69
Ending balance: Collectively evaluated for impairment	$ 69	$ 69

Reflects the aggregate gross carrying amount of all categories of loans and leases held in portfolio, after deducting deferred income, but before deducting the allowance for losses on loans and leases.

Name:	susq_LoansAndLeasesReceivableNetOfUnearnedIncome
Namespace Prefix:	susq
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

A valuation allowance for financing receivables that are expected to be uncollectible.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-URI http://asc.fasb.org/extlink&oid=6965416&loc=SL6953423-111524

-Subparagraph (c)(1)

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Charge to expense for financing receivables that are expected to be uncollectible.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesProvisions
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Reduction to the allowance for credit losses related to collections on financing receivables which have been partially or fully charged off as bad debts.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesRecoveries
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Reduction to the allowance for credit losses related to financing receivables deemed uncollectible.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant