Basis of Presentation and Summary of Significant Accounting Policies (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, plant and equipment
Depreciation expense	$ 85.5	$ 65.9	$ 51.1
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