Employee Benefit Plans (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, long-term rate of return on assets	7.50%	7.50%	8.00%
Defined benefit plan, estimated future employer contribution in next fiscal year	$ 2.0
Defined benefit plan, plan assets at fair value, valuation techniques and inputs	The fair value of plan assets was determined based on publicly quoted market prices for identical assets, which are classified as Level 1 observable inputs.
Defined benefit plan, significant concentrations of risk	Concentrations of risk within our equity portfolio are investments classified within the following sectors: technology, financial services, consumer cyclical goods, healthcare and industrial, which represents approximately 17%, 16%, 15%, 15% and 12% of total equity investments, respectively.
Defined contribution plan, compensation expense	$ 3.2	$ 3.1	$ 3.3
Technology Sector [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, significant concentrations of risk	0.17
Financial Services Sector [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, significant concentrations of risk	0.16
Consumer Cyclical Goods Sector [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, significant concentrations of risk	0.15
Healthcare Sector [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, significant concentrations of risk	0.15
Industrial Sector [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, significant concentrations of risk	0.12