Supplemental Condensed Consolidated Financial Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands		Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents		$ 612		$ 6,452	$ 91,557		$ 701
Accounts receivable, net of allowance for doubtful accounts		77,994		119,397
Materials and supplies		524		473
Current derivative asset		5,959		12,870
Income taxes receivable		2,405		2,054
Assets held for sale		17,299		22,511
Prepaid expenses and other		12,472		6,602
Total current assets		117,265		170,359
Oil and natural gas properties on the full cost method:
Proved properties		6,312,461		6,018,568
Unproved properties not being amortized		282,356		330,216
Drilling equipment		1,290,222		1,284,419
Gas gathering and processing equipment		806,862		767,388
Saltwater disposal systems		69,499		68,339
Corporate land and building		59,080		59,081
Transportation equipment		30,088		29,524
Other		57,431		57,507
Property, plant, and equipment, gross		8,907,999		8,615,042
Less accumulated depreciation, depletion, amortization, and impairment		6,522,621		6,182,726
Net property and equipment		2,385,378		2,432,316
Intercompany receivable		0		0
Goodwill (Note 2)		0		62,808
Investments		0		0
Non-current derivative asset		128		0
Operating right of use asset		7,315		0
Other assets		29,823		32,570
Total assets	[1]	2,539,909		2,698,053
Current liabilities:
Accounts payable		80,414		149,945
Accrued liabilities		73,274		49,664
Current operating lease liability		4,291		0
Current portion of other long-term liabilities		15,402		14,250
Total current liabilities		173,381		213,859
Intercompany debt		0		0
Long-term debt		784,352		644,475
Non-current derivative liability		107		293
Operating lease liability		2,800		0
Other long-term liabilities		96,360		101,234
Deferred income taxes		91,676		144,748
Shareholders' equity:
Preferred stock, $1.00 par value, 5,000,000 shares authorized, none issued		0		0
Common stock, $.20 par value, 175,000,000 shares authorized		10,590		10,414
Capital in excess of par value		644,042		628,108
Contributions from Unit		0		0
Accumulated other comprehensive income (loss)		0		(481)
Retained earnings		534,115		752,840
Total shareholders’ equity attributable to Unit Corporation		1,188,747		1,390,881
Non-controlling interests in consolidated subsidiaries		202,486		202,563
Total shareholders' equity		1,391,233	$ 1,593,232	1,593,444	1,669,365	$ 1,643,654	1,345,560
Total liabilities and shareholders' equity	[1]	2,539,909		2,698,053
Consolidating Adjustments [Member]
Current assets:
Cash and cash equivalents		0		0	0		0
Accounts receivable, net of allowance for doubtful accounts		(7,431)		(14,344)
Materials and supplies		0		0
Current derivative asset		0		0
Income taxes receivable		0		0
Assets held for sale		0		0
Prepaid expenses and other		0		0
Total current assets		(7,431)		(14,344)
Oil and natural gas properties on the full cost method:
Proved properties		0		0
Unproved properties not being amortized		0		0
Drilling equipment		0		0
Gas gathering and processing equipment		0		0
Saltwater disposal systems		0		0
Corporate land and building		0		0
Transportation equipment		0		0
Other		0		0
Property, plant, and equipment, gross		0		0
Less accumulated depreciation, depletion, amortization, and impairment		0		0
Net property and equipment		0		0
Intercompany receivable		(1,093,689)		(950,916)
Goodwill (Note 2)		0		0
Investments		(964,822)		(1,160,444)
Non-current derivative asset		0
Operating right of use asset		(56)
Other assets		0		0
Total assets		(2,065,998)		(2,125,704)
Current liabilities:
Accounts payable		(7,431)		(13,576)
Accrued liabilities		(468)		(468)
Current operating lease liability		(6)
Current portion of other long-term liabilities		(6)		0
Total current liabilities		(7,911)		(14,044)
Intercompany debt		(1,093,689)		(950,916)
Long-term debt		0		0
Non-current derivative liability		0		0
Operating lease liability		(50)
Other long-term liabilities		(602)		(300)
Deferred income taxes		0		0
Shareholders' equity:
Preferred stock, $1.00 par value, 5,000,000 shares authorized, none issued		0		0
Common stock, $.20 par value, 175,000,000 shares authorized		0		0
Capital in excess of par value		(242,963)		(242,963)
Contributions from Unit		(1,272)		(792)
Accumulated other comprehensive income (loss)		0		0
Retained earnings		(719,511)		(916,689)
Total shareholders’ equity attributable to Unit Corporation		(963,746)		(1,160,444)
Non-controlling interests in consolidated subsidiaries		0		0
Total shareholders' equity		(963,746)		(1,160,444)
Total liabilities and shareholders' equity		(2,065,998)		(2,125,704)
Parent [Member]
Current assets:
Cash and cash equivalents		505		403	82,267		510
Accounts receivable, net of allowance for doubtful accounts		1,863		2,539
Materials and supplies		0		0
Current derivative asset		5,959		12,870
Income taxes receivable		2,405		243
Assets held for sale		0		0
Prepaid expenses and other		2,879		1,993
Total current assets		13,611		18,048
Oil and natural gas properties on the full cost method:
Proved properties		0		0
Unproved properties not being amortized		0		0
Drilling equipment		0		0
Gas gathering and processing equipment		0		0
Saltwater disposal systems		0		0
Corporate land and building		0		0
Transportation equipment		9,713		9,273
Other		28,876		28,584
Property, plant, and equipment, gross		38,589		37,857
Less accumulated depreciation, depletion, amortization, and impairment		32,217		27,504
Net property and equipment		6,372		10,353
Intercompany receivable		1,093,689		950,916
Goodwill (Note 2)		0		0
Investments		964,822		1,160,444
Non-current derivative asset		128
Operating right of use asset		52
Other assets		8,558		8,225
Total assets		2,087,232		2,147,986
Current liabilities:
Accounts payable		9,223		8,697
Accrued liabilities		39,000		28,230
Current operating lease liability		22
Current portion of other long-term liabilities		1,069		812
Total current liabilities		49,314		37,739
Intercompany debt		0		0
Long-term debt		780,252		644,475
Non-current derivative liability		107		293
Operating lease liability		29
Other long-term liabilities		14,367		13,134
Deferred income taxes		54,416		60,983
Shareholders' equity:
Preferred stock, $1.00 par value, 5,000,000 shares authorized, none issued		0		0
Common stock, $.20 par value, 175,000,000 shares authorized		10,590		10,414
Capital in excess of par value		644,042		628,108
Contributions from Unit		0		0
Accumulated other comprehensive income (loss)		0		0
Retained earnings		534,115		752,840
Total shareholders’ equity attributable to Unit Corporation		1,188,747		1,391,362
Non-controlling interests in consolidated subsidiaries		0		0
Total shareholders' equity		1,188,747		1,391,362
Total liabilities and shareholders' equity		2,087,232		2,147,986
Combined Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents		104		208	251		191
Accounts receivable, net of allowance for doubtful accounts		62,662		94,526
Materials and supplies		524		473
Current derivative asset		0		0
Income taxes receivable		0		1,811
Assets held for sale		17,299		22,511
Prepaid expenses and other		3,673		3,560
Total current assets		84,262		123,089
Oil and natural gas properties on the full cost method:
Proved properties		6,312,461		6,018,568
Unproved properties not being amortized		282,356		330,216
Drilling equipment		1,290,222		1,284,419
Gas gathering and processing equipment		0		0
Saltwater disposal systems		69,499		68,339
Corporate land and building		59,080		59,081
Transportation equipment		17,002		17,165
Other		28,555		28,923
Property, plant, and equipment, gross		8,059,175		7,806,711
Less accumulated depreciation, depletion, amortization, and impairment		6,090,830		5,790,481
Net property and equipment		1,968,345		2,016,230
Intercompany receivable		0		0
Goodwill (Note 2)		0		62,808
Investments		0		0
Non-current derivative asset		0
Operating right of use asset		1,855
Other assets		9,958		6,793
Total assets		2,064,420		2,208,920
Current liabilities:
Accounts payable		64,771		122,610
Accrued liabilities		27,350		16,409
Current operating lease liability		941
Current portion of other long-term liabilities		7,316		6,563
Total current liabilities		100,378		145,582
Intercompany debt		1,093,642		948,707
Long-term debt		0		0
Non-current derivative liability		0		0
Operating lease liability		883
Other long-term liabilities		72,219		73,713
Deferred income taxes		37,260		83,765
Shareholders' equity:
Preferred stock, $1.00 par value, 5,000,000 shares authorized, none issued		0		0
Common stock, $.20 par value, 175,000,000 shares authorized		0		0
Capital in excess of par value		45,921		45,921
Contributions from Unit		0		0
Accumulated other comprehensive income (loss)		0		(481)
Retained earnings		714,117		911,713
Total shareholders’ equity attributable to Unit Corporation		760,038		957,153
Non-controlling interests in consolidated subsidiaries		0		0
Total shareholders' equity		760,038		957,153
Total liabilities and shareholders' equity		2,064,420		2,208,920
Combined Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents		3		5,841	$ 9,039		$ 0
Accounts receivable, net of allowance for doubtful accounts		20,900		36,676
Materials and supplies		0		0
Current derivative asset		0		0
Income taxes receivable		0		0
Assets held for sale		0		0
Prepaid expenses and other		5,920		1,049
Total current assets		26,823		43,566
Oil and natural gas properties on the full cost method:
Proved properties		0		0
Unproved properties not being amortized		0		0
Drilling equipment		0		0
Gas gathering and processing equipment		806,862		767,388
Saltwater disposal systems		0		0
Corporate land and building		0		0
Transportation equipment		3,373		3,086
Other		0		0
Property, plant, and equipment, gross		810,235		770,474
Less accumulated depreciation, depletion, amortization, and impairment		399,574		364,741
Net property and equipment		410,661		405,733
Intercompany receivable		0		0
Goodwill (Note 2)		0		0
Investments		0		0
Non-current derivative asset		0
Operating right of use asset		5,464
Other assets		11,307		17,552
Total assets		454,255		466,851
Current liabilities:
Accounts payable		13,851		32,214
Accrued liabilities		7,392		5,493
Current operating lease liability		3,334
Current portion of other long-term liabilities		7,023		6,875
Total current liabilities		31,600		44,582
Intercompany debt		47		2,209
Long-term debt		4,100		0
Non-current derivative liability		0		0
Operating lease liability		1,938
Other long-term liabilities		10,376		14,687
Deferred income taxes		0		0
Shareholders' equity:
Preferred stock, $1.00 par value, 5,000,000 shares authorized, none issued		0		0
Common stock, $.20 par value, 175,000,000 shares authorized		0		0
Capital in excess of par value		197,042		197,042
Contributions from Unit		1,272		792
Accumulated other comprehensive income (loss)		0		0
Retained earnings		5,394		4,976
Total shareholders’ equity attributable to Unit Corporation		203,708		202,810
Non-controlling interests in consolidated subsidiaries		202,486		202,563
Total shareholders' equity		406,194		405,373
Total liabilities and shareholders' equity		$ 454,255		$ 466,851

[1] Unit Corporation's consolidated total assets as of September 30, 2019 include total current and long-term assets of its variable interest entity (VIE) (Superior Pipeline Company, L.L.C.) of $24.1 million and $427.4 million, respectively, which can only settle obligations of the VIE. Unit Corporation's consolidated total liabilities as of September 30, 2019 include total current and long-term liabilities of the VIE of $29.4 million and $15.8 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, 2018 include total current and long-term assets of the VIE of $40.1 million and $423.3 million, respectively, which can only settle obligations of the VIE. Unit Corporation's consolidated total liabilities as of December 31, 2018 include total current and long-term liabilities of the VIE of $42.8 million and $14.7 million, respectively, for which the creditors of the VIE have no recourse to Unit Corporation. See Note 15 – Variable Interest Entity Arrangements.