Related Party Transactions (Details) (Affiliated Entity of Director [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Affiliated Entity of Director [Member]
Related Party Transaction [Line Items]
Related party disbursements for legal services	$ 0.3	$ 0.5	$ 0.4