Retirement Savings Plan (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Postemployment Benefits [Abstract]
Percentage of employee compensation plus matching contribution	100.00%
Percentage of maximum limit for employees to contribute their cash compensation	75.00%
Percentage of employee contribution	4.00%
Total plan expenses	$ 1.6	$ 0.8	$ 3.0	$ 2.1