CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income	$ 42,412	$ 24,691
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	75,592	59,629
Long-lived asset impairment	5,310	4,477
Amortization of deferred financing costs	1,952	1,439
Amortization of debt discount	576	483
Amortization of terminated interest rate swaps	1,609	1,865
Interest rate swaps	(7)	151
Unit-based compensation expense	839	974
Provision for doubtful accounts	469	435
Gain on sale of property, plant and equipment	(2,062)	(843)
Changes in assets and liabilities, net of acquisitions:
Accounts receivable, trade	(8,670)	(12,451)
Other assets and liabilities	2,075	3,335
Net cash provided by operating activities	120,095	84,185
Cash flows from investing activities:
Capital expenditures	(138,918)	(131,921)
Payment for business acquisition		(351,121)
Proceeds from sale of property, plant and equipment	11,148	1,670
(Increase) decrease in amounts due from affiliates, net	(511)	4,181
Net cash used in investing activities	(128,281)	(477,191)
Cash flows from financing activities:
Proceeds from borrowings of long-term debt	247,000	564,798
Repayments of long-term debt	(165,500)	(281,500)
Distributions to unitholders	(71,226)	(61,932)
Net proceeds from issuance of common units	1,268	169,471
Net proceeds from sale of general partner units		3,573
Payments for debt issuance costs	(1,311)	(6,923)
Payments for settlement of interest rate swaps that include financing elements	(1,877)	(1,894)
Purchases of treasury units	(274)	(285)
Capital contribution from limited partners and general partner		7,555
Net cash provided by financing activities	8,080	392,863
Net decrease in cash and cash equivalents	(106)	(143)
Cash and cash equivalents at beginning of period	295	182
Cash and cash equivalents at end of period	189	39
Supplemental disclosure of non-cash transactions:
Non-cash capital contribution from limited and general partner	6,328	4,021
Contract operations equipment acquired/exchanged, net	101,503	$ (10,624)
Intangible assets allocated in contract operations acquisition	1,055
Non-cash capital contribution due to the contract operations acquisition	7,608
Common units issued in contract operations acquisition	100,267
General partner units issued in contract operations acquisition	$ 2,033