Related Party Transactions Narrative (Details) (Affiliated Entity [Member], USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012 Employees
Related Party Transaction [Line Items]
Related party management services fees and other arrangements	$ 10.98
Number of employees transferred	37
Executive Services Fee [Member]
Related Party Transaction [Line Items]
Related party management services fees and other arrangements	1.74
Corporate Services Fee [Member]
Related Party Transaction [Line Items]
Related party management services fees and other arrangements	$ 9.24