XML 112 R51.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Sale of NAC Subsidiary (Narrative) (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 6 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Mar. 31, 2013 | Jun. 30, 2013 | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011 | Mar. 15, 2013
Discontinued Operation, Additional Disclosures [Abstract] |  |  |  |  |  |
Goodwill |  |  | $ 0 | $ 6.8 |  | $ 6.8
Proceeds from sale of subsidiary |  | 43.2 | 43.2 | 0 | 0 |
Gain on sale of subsidiary | 35.6 |  | 35.6 | 0 | 0 |
Net assets and liabilities of subsidiary |  |  |  |  |  | 5.5
Transaction costs for sale of subsidiary |  |  |  |  |  | $ 2.1

X
- Details
Name: | us-gaap_DiscontinuedOperationAdditionalDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Gain (loss) from sale or disposal of an organization or integrated set of activities (for example, but not limited to, a partnership or corporation) engaged in providing a product or service in a commercial, industrial, or professional environment. + References No definition available. + Details
Name: | us-gaap_GainLossOnSaleOfBusiness
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266 + Details
Name: | us-gaap_Goodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromDivestitureOfBusinesses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Net assets and liabilities of subsidiary + References No definition available. + Details
Name: | usu_NetAssetsAndLiabilitiesOfSubsidiary
Namespace Prefix: | usu_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Transaction costs for sale of subsidiary + References No definition available. + Details
Name: | usu_TransactionCostsForSaleOfSubsidiary
Namespace Prefix: | usu_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant