Legal Proceedings (Details) (Class Action Lawsuit, USD $) In Millions, unless otherwise specified	Jun. 19, 2012 Approved by Court on June 19, 2012 Securities Class Action Complaint Directors and Officers Liability Insurers	Jun. 30, 2012 Pending Litigation ERISA Class Action Suit Company's Fiduciary Liability Insurers
Loss Contingencies [Line Items]
Liability Insurers Settlement Fund	$ 25.0	$ 2.1