Note 9 - Accrued Expenses (Detail) (Maximum [Member])	Jun. 30, 2012	Dec. 31, 2011
Maximum [Member]
Accrued Expense, Portion of Current Liabilities, Percentage	5.00%	5.00%

The percent of total current liabilites above which each single item would need to be separately disclosed.

No definition available.

Name:	usak_AccruedExpensePortionOfCurrentLiabilitiesPercentage
Namespace Prefix:	usak_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant