Summary of Significant Accounting Policies (Details 2) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Accounts Receivable, net
Accounts receivable written off	$ 0.0	$ 0.0
Allowance for expected prompt-pay discounts	$ 4.9		$ 4.1