Long-Lived Asset Impairment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Long-lived asset impairment
Long-lived asset impairment	$ 12,810	$ 5,350	$ 29,560
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	110	110	260
Horsepower of long-lived assets that the entity determined to sell or re-utilize key components	30,000	25,000	71,000
Long-lived asset impairment	10,100	5,400	22,200
Idle compressor units previously impaired
Long-lived asset impairment
Long-lived asset impairment	2,300		7,400
Other long lived assets
Long-lived asset impairment
Long-lived asset impairment	$ 400