Deferred Compensation Plan (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deferred Compensation Plan (Details) [Abstract]
Maximum deferral % of base compensation allowed to participants of deferred compensation plan	50.00%
Maximum deferral % of bonus compensation allowed to participants of deferred compensation plan	100.00%
Our discretionary contributions	$ 0.6	$ 0.1	$ 0.1
Deferred compensation plan liability	$ 5.0	$ 2.9