Restructuring Costs Narrative (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		$ 6.2
Unrelated to Tulsa Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	$ 2.7	2.7
Tulsa Regional Office [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	3.5
One-time Termination Benefits [Member] | Unrelated to Tulsa Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		2.7
One-time Termination Benefits [Member] | Tulsa Regional Office [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	5.5	5.5
Restructuring and Related Cost, Incurred Cost	2.8	2.8
Employee Relocation [Member] | Tulsa Regional Office [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	2.8	2.8
Restructuring and Related Cost, Incurred Cost	0.7	0.7
Facility Closing [Member] | Tulsa Regional Office [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	3.9	3.9
Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	8.0	8.0
Minimum [Member] | Tulsa Regional Office [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	5.3	5.3
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	12.0	12.0
Maximum [Member] | Tulsa Regional Office [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	$ 9.3	$ 9.3