Variable Interest Entity Arrangements (Schedule of Assets and Liabilities) (Details) - USD ($) $ in Thousands		Sep. 30, 2021	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents		$ 49,566	$ 12,145	$ 32,940	$ 571
Accounts receivable, net of allowance for doubtful accounts		72,405	57,846
Prepaid expenses and other		6,120	11,212
Total current assets		128,113	82,922
Property and equipment:
Gas gathering and processing equipment		259,642	251,404
Transportation equipment		3,750	3,130
Property, plant, and equipment, gross		562,595	600,989
Less accumulated depreciation, depletion, amortization, and impairment		103,794	54,189
Net property and equipment		458,801	546,800
Operating right of use asset		13,800	5,592
Other assets		16,086	14,389
Total assets	[1]	616,800	649,703
Current liabilities:
Accounts payable		47,106	37,368
Accrued liabilities		26,979	25,204
Current operating lease liability		4,399	4,075
Current portion of other long-term liabilities		6,522	11,168
Total current liabilities		158,480	80,347
Operating lease liability		9,387	1,445
Long-term debt (Note 9)		3,100	98,400
VIE
Current assets:
Cash and cash equivalents		12,286	11,642
Accounts receivable, net of allowance for doubtful accounts		36,487	27,427
Prepaid expenses and other		2,540	6,746
Total current assets		51,313	45,815
Property and equipment:
Gas gathering and processing equipment		259,642	251,403
Transportation equipment		2,086	1,748
Property, plant, and equipment, gross		261,728	253,151
Less accumulated depreciation, depletion, amortization, and impairment		34,878	10,466
Net property and equipment		226,850	242,685
Operating right of use asset		3,926	2,823
Other assets		1,961	2,309
Total assets		284,050	293,632
Current liabilities:
Accounts payable		26,921	17,045
Accrued liabilities		6,441	3,777
Current operating lease liability		1,570	1,762
Current portion of other long-term liabilities		1,919	5,799
Total current liabilities		36,851	28,383
Operating lease liability		2,356	1,013
Other long-term liabilities		158	1,589
Total liabilities		42,465	30,985
Long-term debt (Note 9)		$ 3,100	$ 0

[1] Unit Corporation's consolidated total assets as of September 30, 2021 include total current and long-term assets of its variable interest entity (VIE) (Superior Pipeline Company, L.L.C.) of $51.3 million and $232.7 million, respectively, which can only settle obligations of the VIE. Unit Corporation's consolidated cash and cash equivalents of $49.6 million includes $12.3 million held by its VIE. Unit Corporation's consolidated total liabilities as of September 30, 2021 include total current and long-term liabilities of the VIE of $36.9 million and $5.6 million, respectively, for which the creditors of the VIE have no recourse to Unit Corporation. Unit Corporation's consolidated total assets as of December 31, 2020 include total current and long-term assets of the VIE of $45.8 million and $247.8 million, respectively, which can only settle obligations of the VIE. Unit Corporation's consolidated total liabilities as of December 31, 2020 include total current and long-term liabilities of the VIE of $28.4 million and $2.6 million, respectively, for which the creditors of the VIE have no recourse to Unit Corporation. See Note 16 – Variable Interest Entity Arrangements.