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	May 31, 2012
Goodwill [Line Items]
Goodwill	$ 82,746	$ 82,746
Future economic benefit period, in years	10 years
Fair value of the wealth management reporting unit exceeding carrying value	45.90%	63.40%
Annual [Member]
Goodwill [Line Items]
Discount rate	18.40%	17.50%
Weighted-average increase in revenues	5.00%	6.00%
Weighted-average increase in expenses	3.00%	5.00%

Discount Rate Used To Determine Fair Value Of Wealth Management Reporting Unit

No definition available.

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

Future Economic Benefit Period Wealth Management Reporting Unit

No definition available.

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

Goodwill Allocated To 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 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 Used To Determine Fair Value Of 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 Used To Determine Fair Value Of Wealth Management Reporting Unit

No definition available.

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