Goodwill (Factors Used to Measure Goodwill in Income Approach) (Detail) (Wealth Management Reporting Unit [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
May 31, 2013
Goodwill [Line Items]
Goodwill	$ 82,746
Future economic benefit period, in years	10 years
Fair value of the wealth management reporting unit exceeding carrying value	45.90%
Annual [Member]
Goodwill [Line Items]
Discount rate	18.40%
Weighted-average increase in revenues	5.00%
Weighted-average increase in expenses	3.00%

Discount rate factor used, in part, to determine the fair value of the wealth management reporting unit.

No definition available.

Name:	susq_DiscountRateUsedToDetermineFairValueOfWealthManagementReportingUnit
Namespace Prefix:	susq_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Time period over which the reporting unit's future earnings are converted.

No definition available.

Name:	susq_FutureEconomicBenefitPeriodWealthManagementReportingUnit
Namespace Prefix:	susq_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Carrying amount of goodwill allocated to the wealth management reporting unit.

No definition available.

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

Percentage by which the fair value of the wealth management reporting unit exceeded its carrying value.

No definition available.

Name:	susq_PercentageByWhichWealthManagementReportingUnitExceededItsCarryingValue
Namespace Prefix:	susq_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Weighted average increase in expenses factor used, in part, to determine the fair value of the wealth management reporting unit.

No definition available.

Name:	susq_WeightedAverageIncreaseInExpensesUsedToDetermineFairValueOfWealthManagementReportingUnit
Namespace Prefix:	susq_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Weighted average increase in revenues factor used, in part, to determine the fair value of the wealth management reporting unit.

No definition available.

Name:	susq_WeightedAverageIncreaseInRevenuesUsedToDetermineFairValueOfWealthManagementReportingUnit
Namespace Prefix:	susq_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration