Consolidated Variable Interest Entities - Balance Sheets (Details) - Variable Interest Entity, Primary Beneficiary - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
EQGP and EQM | Cash and cash equivalents
Variable Interest Entity [Line Items]
Assets	$ 684,456	$ 2,857
EQGP and EQM | Accounts receivable
Variable Interest Entity [Line Items]
Assets	47,587	28,804
EQGP and EQM | Prepaid expenses and other
Variable Interest Entity [Line Items]
Assets	9,556	8,470
EQGP and EQM | Property, plant and equipment, net
Variable Interest Entity [Line Items]
Assets	3,922,144	2,804,059
EQGP and EQM | Goodwill
Variable Interest Entity [Line Items]
Assets	37,954	0
EQGP and EQM | Intangible assets, net
Variable Interest Entity [Line Items]
Assets	596,887	0
EQGP and EQM | Other assets
Variable Interest Entity [Line Items]
Assets	1,028,418	483,004
EQGP and EQM | Accounts payable
Variable Interest Entity [Line Items]
Liabilities	84,969	47,042
EQGP and EQM | Other current liabilities
Variable Interest Entity [Line Items]
Liabilities	484,884	133,531
EQGP and EQM | Credit facility borrowings
Variable Interest Entity [Line Items]
Liabilities	0	180,000
EQGP and EQM | Senior Notes
Variable Interest Entity [Line Items]
Liabilities	3,453,975	987,352
EQGP and EQM | Other liabilities and credits
Variable Interest Entity [Line Items]
Liabilities	21,442	20,273
RMP | Cash and cash equivalents
Variable Interest Entity [Line Items]
Assets	17,339	10,538
RMP | Accounts receivable
Variable Interest Entity [Line Items]
Assets	9,016	12,246
RMP | Prepaid expenses and other
Variable Interest Entity [Line Items]
Assets	541	1,327
RMP | Property, plant and equipment, net
Variable Interest Entity [Line Items]
Assets	1,479,671	1,431,802
RMP | Goodwill
Variable Interest Entity [Line Items]
Assets	1,346,918	1,346,918
RMP | Other assets
Variable Interest Entity [Line Items]
Assets	8,871	0
RMP | Accounts payable
Variable Interest Entity [Line Items]
Liabilities	30,966	24,634
RMP | Other current liabilities
Variable Interest Entity [Line Items]
Liabilities	2,338	4,200
RMP | Credit facility borrowings
Variable Interest Entity [Line Items]
Liabilities	260,000	286,000
RMP | Other liabilities and credits
Variable Interest Entity [Line Items]
Liabilities	$ 9,572	$ 9,360