Supplemental Condensed Consolidated Financial Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents		$ 3,891	$ 6,452	$ 752		$ 701
Accounts receivable, net of allowance for doubtful accounts		93,875	119,397
Materials and supplies		495	473
Current derivative asset		3,464	12,870
Income taxes receivable		2,054	2,054
Assets held for sale		19,728	22,511
Prepaid expenses and other		7,504	6,602
Total current assets		131,011	170,359
Oil and natural gas properties on the full cost method:
Proved properties		6,104,092	6,018,568
Unproved properties not being amortized		339,957	330,216
Drilling equipment		1,279,735	1,284,419
Gas gathering and processing equipment		781,970	767,388
Saltwater disposal systems		69,010	68,339
Corporate land and building		59,080	59,081
Transportation equipment		30,327	29,524
Other		57,624	57,507
Property, plant, and equipment, gross		8,721,795	8,615,042
Less accumulated depreciation, depletion, amortization, and impairment		6,225,220	6,182,726
Net property and equipment		2,496,575	2,432,316
Intercompany receivable		0	0
Goodwill		62,808	62,808
Investments		1,500	1,500
Operating right of use asset		4,551	0
Other assets		32,735	31,070
Total assets	[1]	2,729,180	2,698,053
Current liabilities:
Accounts payable		132,899	149,945
Accrued liabilities		48,084	49,664
Current operating lease liability		2,369	0
Current portion of other long-term liabilities		14,310	14,250
Total current liabilities		197,662	213,859
Intercompany debt		0	0
Long-term debt less debt issuance costs		685,031	644,475
Non-current derivative liability		475	293
Operating lease liability		1,952	0
Other long-term liabilities		103,832	101,234
Deferred income taxes		144,369	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		10,578	10,414
Capital in excess of par value		633,361	628,108
Contributions from Unit		0	0
Accumulated other comprehensive income (loss)		(457)	(481)	(100)	$ 63
Retained earnings		749,510	752,840
Total shareholders’ equity attributable to Unit Corporation		1,392,992	1,390,881
Non-controlling interests in consolidated subsidiaries		202,867	202,563
Total shareholders' equity		1,595,859	1,593,444	1,357,300		1,345,560
Total liabilities and shareholders' equity	[1]	2,729,180	2,698,053
Consolidating Adjustments [Member]
Current assets:
Cash and cash equivalents		0	0	0		0
Accounts receivable, net of allowance for doubtful accounts		(7,275)	(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		(7,275)	(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		(993,100)	(950,916)
Goodwill		0	0
Investments		(1,171,779)	(1,160,444)
Operating right of use asset		0
Other assets		0	0
Total assets		(2,172,154)	(2,125,704)
Current liabilities:
Accounts payable		(6,404)	(13,576)
Accrued liabilities		(467)	(468)
Current operating lease liability		0
Current portion of other long-term liabilities		0	0
Total current liabilities		(6,871)	(14,044)
Intercompany debt		(993,100)	(950,916)
Long-term debt less debt issuance costs		0	0
Non-current derivative liability		0	0
Operating lease liability		0
Other long-term liabilities		(403)	(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		(1,078)	(792)
Accumulated other comprehensive income (loss)		0	0
Retained earnings		(927,739)	(916,689)
Total shareholders’ equity attributable to Unit Corporation		(1,171,780)	(1,160,444)
Non-controlling interests in consolidated subsidiaries		0	0
Total shareholders' equity		(1,171,780)	(1,160,444)
Total liabilities and shareholders' equity		(2,172,154)	(2,125,704)
Parent [Member]
Current assets:
Cash and cash equivalents		507	403	506		510
Accounts receivable, net of allowance for doubtful accounts		1,879	2,539
Materials and supplies		0	0
Current derivative asset		3,464	12,870
Income taxes receivable		243	243
Assets held for sale		0	0
Prepaid expenses and other		2,190	1,993
Total current assets		8,283	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		9,731	9,273
Other		28,669	28,584
Property, plant, and equipment, gross		38,400	37,857
Less accumulated depreciation, depletion, amortization, and impairment		29,057	27,504
Net property and equipment		9,343	10,353
Intercompany receivable		993,100	950,916
Goodwill		0	0
Investments		1,171,779	1,160,444
Operating right of use asset		10
Other assets		8,758	8,225
Total assets		2,191,273	2,147,986
Current liabilities:
Accounts payable		10,199	8,697
Accrued liabilities		29,654	28,230
Current operating lease liability		9
Current portion of other long-term liabilities		781	812
Total current liabilities		40,643	37,739
Intercompany debt		0	0
Long-term debt less debt issuance costs		685,031	644,475
Non-current derivative liability		475	293
Operating lease liability		0
Other long-term liabilities		14,356	13,134
Deferred income taxes		57,319	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		10,578	10,414
Capital in excess of par value		633,361	628,108
Contributions from Unit		0	0
Accumulated other comprehensive income (loss)		0	0
Retained earnings		749,510	752,840
Total shareholders’ equity attributable to Unit Corporation		1,393,449	1,391,362
Non-controlling interests in consolidated subsidiaries		0	0
Total shareholders' equity		1,393,449	1,391,362
Total liabilities and shareholders' equity		2,191,273	2,147,986
Combined Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents		256	208	246		191
Accounts receivable, net of allowance for doubtful accounts		75,400	94,526
Materials and supplies		495	473
Current derivative asset		0	0
Income taxes receivable		1,811	1,811
Assets held for sale		19,728	22,511
Prepaid expenses and other		2,868	3,560
Total current assets		100,558	123,089
Oil and natural gas properties on the full cost method:
Proved properties		6,104,092	6,018,568
Unproved properties not being amortized		339,957	330,216
Drilling equipment		1,279,735	1,284,419
Gas gathering and processing equipment		0	0
Saltwater disposal systems		69,010	68,339
Corporate land and building		59,080	59,081
Transportation equipment		17,332	17,165
Other		28,955	28,923
Property, plant, and equipment, gross		7,898,161	7,806,711
Less accumulated depreciation, depletion, amortization, and impairment		5,820,157	5,790,481
Net property and equipment		2,078,004	2,016,230
Intercompany receivable		0	0
Goodwill		62,808	62,808
Investments		1,500	1,500
Operating right of use asset		1,762
Other assets		7,929	5,293
Total assets		2,252,561	2,208,920
Current liabilities:
Accounts payable		104,928	122,610
Accrued liabilities		15,342	16,409
Current operating lease liability		658
Current portion of other long-term liabilities		6,606	6,563
Total current liabilities		127,534	145,582
Intercompany debt		993,182	948,707
Long-term debt less debt issuance costs		0	0
Non-current derivative liability		0	0
Operating lease liability		1,015
Other long-term liabilities		76,831	73,713
Deferred income taxes		87,050	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)		(457)	(481)
Retained earnings		921,485	911,713
Total shareholders’ equity attributable to Unit Corporation		966,949	957,153
Non-controlling interests in consolidated subsidiaries		0	0
Total shareholders' equity		966,949	957,153
Total liabilities and shareholders' equity		2,252,561	2,208,920
Combined Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents		3,128	5,841	$ 0		$ 0
Accounts receivable, net of allowance for doubtful accounts		23,871	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		2,446	1,049
Total current assets		29,445	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		781,970	767,388
Saltwater disposal systems		0	0
Corporate land and building		0	0
Transportation equipment		3,264	3,086
Other		0	0
Property, plant, and equipment, gross		785,234	770,474
Less accumulated depreciation, depletion, amortization, and impairment		376,006	364,741
Net property and equipment		409,228	405,733
Intercompany receivable		0	0
Goodwill		0	0
Investments		0	0
Operating right of use asset		2,779
Other assets		16,048	17,552
Total assets		457,500	466,851
Current liabilities:
Accounts payable		24,176	32,214
Accrued liabilities		3,555	5,493
Current operating lease liability		1,702
Current portion of other long-term liabilities		6,923	6,875
Total current liabilities		36,356	44,582
Intercompany debt		(82)	2,209
Long-term debt less debt issuance costs		0	0
Non-current derivative liability		0	0
Operating lease liability		937
Other long-term liabilities		13,048	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		1,078	792
Accumulated other comprehensive income (loss)		0	0
Retained earnings		6,254	4,976
Total shareholders’ equity attributable to Unit Corporation		204,374	202,810
Non-controlling interests in consolidated subsidiaries		202,867	202,563
Total shareholders' equity		407,241	405,373
Total liabilities and shareholders' equity		$ 457,500	$ 466,851

[1] Unit Corporation's consolidated total assets as of March 31, 2019 include total current and long-term assets of its variable interest entity (VIE) (Superior Pipeline Company, L.L.C.) of $28.9 million and $428.1 million, respectively, which can only be used to settle obligations of the VIE. Unit Corporation's consolidated total liabilities as of March 31, 2019 include total current and long-term liabilities of the VIE of $36.0 million and $14.0 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 be used to 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 14 – Variable Interest Entity Arrangements.