Significant Customer - (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting [Abstract]
Revenue, largest customer, amount	$ 101.0	$ 113.5	$ 116.5
Revenue, largest customer, percentage	24.10%	26.70%	29.40%
Revenue related to sale of major customer's business segment		3.2
Accounts receivable, largest customer, amount	$ 11.0	$ 12.6
Concentration Risk, Percentage	10.00%	10.00%	10.00%