Employee Benefit Plans Supplemental Executive Retirement Plan and Defined Contribution (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 plan	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Supplemental executive retirement plan liability	$ 0.3	$ 0.2
U.S.
Defined Benefit Plan Disclosure [Line Items]
Number of defined contribution plans	2
Employer discretionary contribution amount	0.4	0.7	0.6
UK
Defined Benefit Plan Disclosure [Line Items]
Employer discretionary contribution amount	$ 2.2	$ 2.2	$ 2.2