Allowance For Loan & Lease Losses (Narrative) (Detail) (USD $)	Jun. 30, 2014
Allowance For Loan And Lease Losses [Abstract]
Watch List Relationship Threshold	$ 1,000,000

Relationship threshold on substandard, special mention, and pass rated loans, on the watch list, to determine if the loans should be reviewed on a quarterly basis.

No definition available.

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