Investments in Unconsolidated Affiliates (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) item mi	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Investments in unconsolidated affiliates
Balance at beginning of period	$ 722,478	$ 709,639
Additional investments	2,070	25,267	$ 154,359
Equity in earnings of unconsolidated affiliates	90,451	86,430	51,315
Distributions from unconsolidated affiliates	(118,990)	(98,858)	(64,320)
Balance at end of period	696,009	722,478	709,639
Summarized Financial Information of Unconsolidated Affiliates
Current assets	83,804	93,931
Total assets	5,544,001	5,610,912	6,282,878
Current liabilities	114,009	94,005
Partners' capital	2,286,698	2,418,286	3,143,414
Total liabilities and stockholders' equity	5,544,001	5,610,912
Revenues	898,202	900,719	792,588
Income from operations	555,327	(117,638)	(398,493)
Net income attributable to unconsolidated affiliates, including noncontrolling interest	331,617	(122,527)	(355,114)
Unconsolidated Affiliates
Summarized Financial Information of Unconsolidated Affiliates
Current assets	74,704	85,386
Noncurrent assets	1,602,093	1,652,196
Total assets	1,676,797	1,737,582
Current liabilities	8,375	9,242
Noncurrent liabilities	4,827	5,225
Noncontrolling interest	161,842	169,218
Partners' capital	1,501,753	1,553,897
Total liabilities and stockholders' equity	1,676,797	1,737,582
Revenues	333,565	321,880	254,868
Operating expenses	130,080	122,660	105,218
Income from operations	203,485	199,220	149,650
Net income attributable to unconsolidated affiliates, including noncontrolling interest	236,444	230,564	173,265
Net income attributable to unconsolidated affiliates	$ 245,256	238,991	181,448
Stonewall
Equity Method Investments
Ownership percentage	15.00%
Number of miles of pipeline | mi	67
Investments in unconsolidated affiliates
Balance at beginning of period	$ 137,632	140,458
Equity in earnings of unconsolidated affiliates	6,560	6,924
Distributions from unconsolidated affiliates	(13,620)	(9,750)
Balance at end of period	$ 130,572	137,632	140,458
MarkWest Joint Venture
Equity Method Investments
Ownership percentage	50.00%
Percentage of interest held by joint venture in third party fractionator in Ohio	33.33%
Number of fractionators | item	2
Investments in unconsolidated affiliates
Balance at beginning of period	$ 584,846	569,181
Additional investments	2,070	25,267
Equity in earnings of unconsolidated affiliates	83,891	79,506
Distributions from unconsolidated affiliates	(105,370)	(89,108)
Balance at end of period	$ 565,437	$ 584,846	$ 569,181