| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 |
| | 8-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Revenues: | | | | | | | | |
| Total revenues | 369.6 | 400.6 | 383.5 | 443.5 | 506.7 | 488.7 | 402.4 | 400.6 |
| Total revenues growth | -7.7% | 4.5% | -13.5% | -12.5% | 3.7% | 21.5% | 0.5% | 3.5% |
| Costs and expenses: | | | | | | | | |
| Operation and maintenance | | 74.2 | 86.0 | 98.7 | 96.9 | 93.9 | 95.3 | 95.0 |
| General and administrative | 44.9 | 58.2 | 73.4 | 55.9 | 52.9 | 54.7 | 52.4 | 45.1 |
| Depreciation and amortization | | 119.1 | 118.1 | 110.4 | 107.1 | 115.5 | 112.2 | 105.1 |
| Transaction costs | 7.0 | 1.7 | 3.0 | 3.0 | | 0.1 | 1.3 | 1.3 |
| Gain on asset sales, net | -0.5 | -0.4 | -0.3 | -1.5 | | 0.5 | 0.1 | |
| Long-lived asset impairments | | 10.2 | 13.1 | 60.5 | 7.2 | 188.7 | 1.8 | 9.3 |
| Total costs and expenses | 143.0 | 690.0 | 673.4 | 818.7 | 371.7 | 1,021.5 | 581.3 | 557.7 |
| Other income (expense), net | | -0.6 | 0.0 | 0.5 | -0.2 | 0.3 | 0.1 | 0.0 |
| Interest expense | -102.5 | -66.2 | -78.9 | -92.0 | -60.5 | -68.1 | -63.8 | -59.1 |
| Loss before income taxes and equity method investment income | -123.1 | -28.2 | 177.7 | -54.6 | 53.3 | 88.6 | -7.8 | -216.3 |
| Income tax benefit (expense) | -0.3 | 0.3 | 0.1 | -1.2 | 0.0 | -0.3 | -0.1 | 0.6 |
| Tax rate | | 1.2% | | | 0.1% | 0.4% | | 0.3% |
| Income from equity method investees | 18.1 | 7.9 | 11.3 | -337.9 | -10.9 | -2.2 | -30.3 | -6.6 |
| Net loss | | -19.9 | 189.1 | -393.7 | 42.4 | 86.1 | -38.2 | -222.2 |
| |
| Less: Net income attributable to Subsidiary Series A Preferred Units | | | | | | | | |
| Net loss attributable to Summit Midstream Partners, LP | -123.5 | -36.6 | 178.9 | | 42.2 | 85.7 | -40.9 | -192.2 |
| |
| Net loss attributable to common limited partners | | | | | | | | |
| Net loss per limited partner unit: | | | | | | | | |
| Common unit - basic (in dollars per share) | $16,414.00 | ($6.57) | $73.22 | ($70.50) | $0.06 | $0.99 | ($0.71) | |
| Common unit - diluted (in dollars per share) | $16,414.00 | ($6.57) | $73.22 | ($70.50) | $0.06 | $0.99 | ($0.71) | |
| |
| Weighted-average limited partner units outstanding: | | | | | | | | |
| Common units - basic (in shares) | | | | | | | | |
| Common units - diluted (in shares) | | | | | | | | |