Business Changes, Risks, Uncertainties and Accounting Developments (Details 3) (MIAC [Member], USD $) In Millions, unless otherwise specified	May 31, 2012 jurisdictions
MIAC [Member]
Business Acquisition [Line Items]
Business Combinations, Percent of Outstanding Common Stock Purchased	100.00%
Business Acquisition, Cost of Acquired Entity, Cash Paid	$ 91.1
Number of Jurisdictions in which Entity is Licensed to Operate	38
Business Acquisition, Purchase Price Allocation, Intangible Assets Other than Goodwill	$ 16.0

Amount of cash paid to acquire the entity.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph f(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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_BusinessAcquisitionCostOfAcquiredEntityCashPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant