Corporate Office Relocation (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Expected restructuring and relocation costs	$ 15.0
Home Office Relocation [Member]
Restructuring Cost and Reserve [Line Items]
Employee severance, retention, relocation, and related costs	16.3	15.4
Home Office Relocation [Member] | Employee severance, retention, and relocation costs [Member]
Restructuring Cost and Reserve [Line Items]
Employee severance, retention, relocation, and related costs	7.6	15.0
Home Office Relocation [Member] | Asset impairments [Member]
Restructuring Cost and Reserve [Line Items]
Employee severance, retention, relocation, and related costs	$ 8.7	$ 0.4