Long-lived Asset Impairment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Long-lived asset impairment
Long-lived asset impairment	$ 29,560	$ 1,060	$ 24,976
Idle compressor units
Long-lived asset impairment
Number of long-lived assets that the entity determined to retire and either sell or re-utilize key components	260		370
Horsepower of long-lived assets that the entity determined to sell or re-utilize key components	71,000		117,000
Long-lived asset impairment	22,200	1,100	24,600
Idle compressor units previously impaired
Long-lived asset impairment
Long-lived asset impairment	$ 7,400		$ 400