Basis of Presentation and Summary of Significant Accounting Policies (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, plant and equipment
Depreciation expense	$ 119.0	$ 100.7	$ 85.5
Compression equipment | Minimum
Property, plant and equipment
Estimated useful life	15 years
Compression equipment | Maximum
Property, plant and equipment
Estimated useful life	30 years
Capitalized overhauls and major improvements | Maximum
Property, plant and equipment
Estimated useful life	7 years