Acquisition Acquisition (Details) (USD $)	12 Months Ended			9 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Aug. 18, 2014	Aug. 11, 2014	Aug. 04, 2014
Business Acquisition [Line Items]
Acquisition purchase price	$ 825,000,000	$ 0	$ 0
Subordinated units converted to common units					6,273,970
Senior Note interest rate	7.25%
Number of units sold to General Partner	1,390,290
Goodwill	233,623,000	72,161,000
Financing expense	(6,750,000)	0	0
Compressor Systems, Inc. [Member]
Business Acquisition [Line Items]
Effective date of acquisition				Aug. 04, 2014
Date of acquisition agreement				Jul. 20, 2014
Acquisition purchase price	825,000,000
Senior Notes	350,000,000
Proceeds from sale of Senior Notes	337,800,000
Number of units sold in public offering	15,280,000
Public offering price per common unit							$ 23.50
Net proceeds from issuance or sale of equity	346,000,000
Gross proceeds from issuance or sale of equity	359,100,000
Number of units subject to underwriters' option							2,292,000
Date of exercise of underwriters' option	Aug. 11, 2014
Net proceeds from exercise of underwriters' option	51,700,000
Gross proceeds from exercise of underwriters' option	53,900,000
Total number of new units issued, including units subject to underwriters' option	17,572,000
General Partner capital contribution						1,100,000	7,300,000
General Partner percentage interest	2.00%
Current assets							101,108,000
Property and equipment							571,264,000
Intangible assets							66,800,000
Goodwill							161,462,000
Total assets acquired							900,634,000
Current liabilities							75,634,000
Total liabilities assumed							75,634,000
Net assets acquired							825,000,000
Nondeductible goodwill	161,500,000
Revenues associated with acquired operations	152,500,000
Depreciation and amortization associated with acquired operations	25,200,000
Income before taxes associated with acquired operations	16,000,000
Transaction costs	5,500,000
Deferred financing costs	16,600,000
Financing expense	6,800,000
Business Acquisition, Pro Forma Information [Abstract]
Revenues	490,545,000	452,800,000
Depreciation and amortization	84,849,000	72,363,000
Net income	$ 13,624,000	$ 19,568,000
Per unit information:
Basic	$ 0.54	$ 0.58
Diluted	$ 0.53	$ 0.58
Net income per basic and diluted subordinated unit	$ 0.54	$ 0.58