Recent Accounting Pronouncements (Details Textual)	6 Months Ended
Jun. 30, 2012
Recent Accounting Pronouncements (Textual) [Abstract]
Minimum probability that the fair value is less than its carrying amount	50.00%

Minimum probability that the fair value is less than its carrying amount.

No definition available.

Name:	subk_MinimumProbabilityThatFairValueIsLessThanItsCarryingAmount
Namespace Prefix:	subk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration