Restructuring Costs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012
Restructuring Costs [Abstract]
Number of regional offices created		1
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs		$ 6.0
Restructuring costs incurred to date	2.3	5.0
Increase (Decrease) in Restructuring Liability [Roll Forward]
Balance at December 31, 2011		0
Costs incurred and charged to expense		5.0
Costs paid or otherwise settled		(4.6)
Balance at June 30, 2012	0.4	0.4
One-time Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs		2.1
Restructuring costs incurred to date	0.8	1.9
Employee Relocation [Member]
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs		3.4
Termination of Lease [Member]
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs		$ 0.5