Condensed Consolidating Statements of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities	$ 462,761	$ 217,580
Cash flows from investing activities
Additions to property, plant and equipment	(521,170)	(545,594)
Purchase of compression assets	(159,210)
Investments in unconsolidated affiliates	(220,378)	(263,710)
Proceeds from sale of assets	14,296	31,696
Net cash used in investing activities	(886,462)	(777,608)
Cash flows from financing activities
Proceeds from long-term borrowings	1,053,471	875,500
Payments on long-term debt borrowings	(1,246,971)	(659,300)
Proceeds from issuance of common units	52,155	399,922
Proceeds from issuance of senior notes	750,000
Distributions to unitholders	(252,145)	(177,430)
Capital contributions from noncontrolling interests	95,441	71,414
Payments on capital lease obligations	(1,983)
Debt issuance costs	(8,777)	(5,377)
Other	1,956	8,328
Net cash provided by financing activities	443,147	513,057
Net increase in cash and cash equivalents	19,446	(46,971)
Cash and cash equivalents, beginning of period	17,229	64,994
Cash and cash equivalents, end of period	36,675	18,023
Eliminations
Cash flows from financing activities
Proceeds from issuance of senior notes
Payments on capital lease obligations
Parent | Reportable Legal Entities
Cash flows from financing activities
Proceeds from issuance of common units	52,155	399,922
Proceeds from issuance of senior notes	750,000
Distributions to unitholders	(252,145)	(177,430)
Payments on capital lease obligations
Debt issuance costs	(8,777)	(660)
Other	1,956	8,328
Intercompany advances, net	(543,189)	(230,160)
Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities	405,796	206,739
Cash flows from investing activities
Additions to property, plant and equipment	(246,455)	(356,868)
Purchase of compression assets	(159,210)
Investments in unconsolidated affiliates	(220,378)	(263,710)
Proceeds from sale of assets	14,296	31,696
Net cash used in investing activities	(611,747)	(588,882)
Cash flows from financing activities
Proceeds from long-term borrowings	1,053,471	875,500
Payments on long-term debt borrowings	(1,246,971)	(659,300)
Proceeds from issuance of senior notes
Payments on capital lease obligations	(1,983)
Debt issuance costs		(4,717)
Intercompany advances, net	401,042	107,444
Net cash provided by financing activities	205,559	318,927
Net increase in cash and cash equivalents	(392)	(63,216)
Cash and cash equivalents, beginning of period	400	63,216
Cash and cash equivalents, end of period	8
Non-Guarantors | Reportable Legal Entities
Cash flows from operating activities	56,965	10,841
Cash flows from investing activities
Additions to property, plant and equipment	(274,715)	(188,726)
Net cash used in investing activities	(274,715)	(188,726)
Cash flows from financing activities
Proceeds from issuance of senior notes
Capital contributions from noncontrolling interests	95,441	71,414
Payments on capital lease obligations
Intercompany advances, net	142,147	122,716
Net cash provided by financing activities	237,588	194,130
Net increase in cash and cash equivalents	19,838	16,245
Cash and cash equivalents, beginning of period	16,829	1,778
Cash and cash equivalents, end of period	$ 36,667	$ 18,023