Commitments and Contingencies--Additional Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 compressor court_case	Dec. 31, 2012	Dec. 31, 2011
Loss Contingencies [Line Items]
Letters of credit outstanding	$ 920	$ 920
Interest paid	107,122	103,350	85,222
Leases, Operating [Abstract]
Rent expense	8,967	8,144	6,715
Maximum remaining term of operating leases	5 years
Remaining payments associated with operating leases	955
Number of Assets	3
Litigation and Claims [Abstract]
Number of court cases	2
Minimum | Pending Litigation
Litigation and Claims [Abstract]
Damages sought	5,000
Letter of Credit
Loss Contingencies [Line Items]
Interest paid	$ 0	$ 0	$ 0
Short-Term [Member]
Leases, Operating [Abstract]
Number of short-term interim agreements	2