Nature of Operations (Details)	12 Months Ended
Dec. 31, 2013 item
Nature of Operations
Number of dental companies merged into the operations of the Company	9

Represents the number of dental entities, indirectly wholly owned subsidiaries of the parent entity merged into the operations of the reporting entity.

No definition available.

Name:	usic_NumberOfDentalEntitiesMergedIntoOperationsOfReportingEntity
Namespace Prefix:	usic_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration