Commitments and Contingencies Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Loss Contingencies [Line Items]
Future minimum rentals under noncancelable subleases	$ 0.5
Operating leases, rent expense	8.1	$ 4.2	$ 3.2
Commitment to purchase	$ 7.8
Vehicles And Equipment [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Capital lease term	3 years
Vehicles And Equipment [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Capital lease term	6 years
Furniture, fixtures and equipment [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Capital lease term	3 years
Operating lease term	1 year
Furniture, fixtures and equipment [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Capital lease term	6 years
Operating lease term	5 years
Building and improvements [Member]
Loss Contingencies [Line Items]
Remaining term on capital lease	8 years
Building and improvements [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Operating lease term	1 year
Building and improvements [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Operating lease term	5 years
Property And Equipment [Member]
Loss Contingencies [Line Items]
Capital lease carrying value	$ 26.3	11.7
Capital leases, accumulated depreciation	$ (21.5)	$ (17.6)