The per share amount of a dividend declared, but not paid, as of the financial reporting date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 32
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

Name:	us-gaap_DividendsPayableAmountPerShare
Namespace Prefix:	us-gaap
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

Subsequent Events (Details)	1 Months Ended
Subsequent Events (Details)	Jun. 30, 2011	Apr. 30, 2012 USD ($)	Jan. 31, 2012 USD ($)	Oct. 31, 2011 USD ($)	Aug. 31, 2011 USD ($)	Jul. 31, 2011 CHF	May 31, 2011 USD ($)
Subsequent Events
Transatlantic shares received of Allied World Switzerland	0.88
Dividends payable per share		$ 0.375	$ 0.375	$ 0.375	$ 0.375		$ 0.375
Par value reduction based on the CHF exchange rate						0.30