Earnings per Share Stock Repurchase (Details) $ in Millions	Sep. 30, 2015 USD ($)
Class A Common Shares [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount	$ 300.0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_EquityClassOfTreasuryStockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration