Commitments and Contingencies (Details 2)	3 Months Ended	1 Months Ended
Mar. 31, 2013	Sep. 08, 2011 Alleged Securities Exchange Act violations item
Commitments and Contingencies
Number of purported class action lawsuits filed		3
Minimum period of right to file a notice to appeal	30 days

The total number of new claims filed pertaining to a loss contingency during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9, 10, 11, 12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_LossContingencyNewClaimsFiledNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration