Guarantees of Registered Securities (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
CURRENT ASSETS: [Abstract]
Cash and cash equivalents	$ 1,019,252	$ 342,514
Receivables - trade and other	463,805		423,839
Other current assets	71,928		81,749
Assets of discontinued operations	23,430		22,954
Total current assets	1,578,415		1,552,550
Property, plant and equipment - gross	7,734,512		7,661,093
Less accumulated depreciation and amortization	1,635,889		1,589,364
Property, plant and equipment - net	6,098,623		6,071,729
Investments in subsidiaries	0		0
Due from affiliates	0		0
Other assets	72,154		75,208
TOTAL ASSETS	7,749,192		7,699,487
CURRENT LIABILITIES: [Abstract]
Accounts payable - trade	64,065		83,004
Deferred revenues	50,250		52,340
Accrued liabilities	106,326		137,495
Liabilities of discontinued operations	21,255		21,255
Total current liabilities	241,896		294,094
Long-term debt	2,009,668		2,009,598
Due to affiliates	0		0
Other liabilities	391,651		390,199
Deferred income taxes - net	499,832		473,872
Shareholders' equity	4,606,145		4,531,724
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	7,749,192		7,699,487
Condensed Consolidating Income Statements [Abstract]
REVENUES	394,238	333,477
COSTS AND EXPENSES: [Abstract]
Direct operating costs (excluding items below)	209,469	182,139
Depreciation and amortization	64,616	58,966
Selling, general and administrative	29,431	23,056
Loss (gain) on disposals of property and equipment	308	(56)
Material charges and other operating expenses	0	4,571
Total costs and expenses	303,824	268,676
INCOME (LOSS) FROM OPERATIONS	90,414	64,801
OTHER INCOME (EXPENSE): [Abstract]
Interest expense, net of interest capitalized	(18,581)	(11,257)
Interest income	359	114
Other - net	(794)	1,337
Total other income (expense) - net	(19,016)	(9,806)
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	71,398	54,995
(Benefit) provision for income taxes	3,264	(504)
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	68,134	55,499
DISCONTINUED OPERATIONS, NET OF TAX	0	(5,982)
EQUITY IN EARNINGS OF SUBSIDIARIES, NET OF TAX	0	0
NET INCOME	68,134	49,517
Statement of Comprehensive Income [Abstract]
NET INCOME	68,134	49,517
Pension and other postretirement benefit adjustments, net of income taxes
Amortization of net loss	4,412	4,087
Amortization of transition obligation	0	77
Amortization of prior service credit	(784)	(775)
OTHER COMPREHENSIVE INCOME	3,628	3,389
COMPREHENSIVE INCOME	71,762	52,906
Consolidated Statement of Cash Flows [Abstract]
NET CASH PROVIDED BY OPERATING ACTIVITIES	103,179	63,281
INVESTING ACTIVITIES [Abstract]
Property, plant and equipment additions	(111,965)	(138,105)
Proceeds from disposals of property, plant and equipment	2,387	928
Investments in consolidated subsidiaries	0
Increase in restricted cash	0	(10,621)
Net cash used in investing activities	(109,578)	(147,798)
FINANCING ACTIVITIES [Abstract]
Repayments of borrowings	0	(12,312)
Advances (to) from affiliates	0	0
Contributions from parent	0	0
Proceeds from borrowings	0	0
Debt issue costs	0	0
Dividends paid to affiliates	0	0
Proceeds from exercise of employee share options	1,531	214
Excess tax benefits from share-based compensation	112	276
Net cash provided by (used in) financing activities	1,643	(11,822)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(4,756)	(96,339)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	1,024,008	438,853
CASH AND CASH EQUIVALENTS, END OF PERIOD	1,019,252	342,514
Rowan Companies Plc [Member]
CURRENT ASSETS: [Abstract]
Cash and cash equivalents	50,834	20,236
Receivables - trade and other	144		107
Other current assets	85		293
Assets of discontinued operations	0		0
Total current assets	51,063		59,028
Property, plant and equipment - gross	0		0
Less accumulated depreciation and amortization	0		0
Property, plant and equipment - net	0		0
Investments in subsidiaries	4,547,980		4,562,016
Due from affiliates	14,370		0
Other assets	0		0
TOTAL ASSETS	4,613,413		4,621,044
CURRENT LIABILITIES: [Abstract]
Accounts payable - trade	473		1,277
Deferred revenues	0		0
Accrued liabilities	0		0
Liabilities of discontinued operations	0		0
Total current liabilities	473		1,277
Long-term debt	0		0
Due to affiliates	8		88,043
Other liabilities	6,787		0
Deferred income taxes - net	0		0
Shareholders' equity	4,606,145		4,531,724
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	4,613,413		4,621,044
Condensed Consolidating Income Statements [Abstract]
REVENUES	0	0
COSTS AND EXPENSES: [Abstract]
Direct operating costs (excluding items below)	0	0
Depreciation and amortization	0	0
Selling, general and administrative	9,212	641
Loss (gain) on disposals of property and equipment	0	0
Material charges and other operating expenses	0	1,675
Total costs and expenses	9,212	2,316
INCOME (LOSS) FROM OPERATIONS	(9,212)	(2,316)
OTHER INCOME (EXPENSE): [Abstract]
Interest expense, net of interest capitalized	0	0
Interest income	42	5
Other - net	2,499	0
Total other income (expense) - net	2,541	5
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(6,671)	(2,311)
(Benefit) provision for income taxes	0	0
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	(6,671)	(2,311)
DISCONTINUED OPERATIONS, NET OF TAX	0	0
EQUITY IN EARNINGS OF SUBSIDIARIES, NET OF TAX	74,805	51,828
NET INCOME	68,134	49,517
Statement of Comprehensive Income [Abstract]
NET INCOME	68,134	49,517
Pension and other postretirement benefit adjustments, net of income taxes
Amortization of net loss	4,412	4,087
Amortization of transition obligation	0	77
Amortization of prior service credit	(784)	(775)
OTHER COMPREHENSIVE INCOME	3,628	3,389
COMPREHENSIVE INCOME	71,762	52,906
Consolidated Statement of Cash Flows [Abstract]
NET CASH PROVIDED BY OPERATING ACTIVITIES	(5,076)	(1,766)
INVESTING ACTIVITIES [Abstract]
Property, plant and equipment additions	0	0
Proceeds from disposals of property, plant and equipment	0	0
Investments in consolidated subsidiaries	0
Increase in restricted cash		0
Net cash used in investing activities	0	0
FINANCING ACTIVITIES [Abstract]
Repayments of borrowings	0	0
Advances (to) from affiliates	(4,249)	530
Contributions from parent	0	0
Proceeds from borrowings	0	0
Debt issue costs	0	0
Dividends paid to affiliates	0	0
Proceeds from exercise of employee share options	1,531	0
Excess tax benefits from share-based compensation	0	0
Net cash provided by (used in) financing activities	(2,718)	530
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(7,794)	(1,236)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	58,628	21,472
CASH AND CASH EQUIVALENTS, END OF PERIOD	50,834	20,236
Rowan Companies, Inc. [Member]
Condensed Financial Statements, Captions [Line Items]
Ownership interest (in hundredths)	100.00%
CURRENT ASSETS: [Abstract]
Cash and cash equivalents	266,202	50,295
Receivables - trade and other	119,930		95,386
Other current assets	37,276		46,614
Assets of discontinued operations	23,430		22,954
Total current assets	446,838		393,039
Property, plant and equipment - gross	1,305,888		1,311,987
Less accumulated depreciation and amortization	483,092		487,147
Property, plant and equipment - net	822,796		824,840
Investments in subsidiaries	5,071,971		1,355,968
Due from affiliates	1,882,819		4,524,480
Other assets	37,073		37,787
TOTAL ASSETS	8,261,497		7,136,114
CURRENT LIABILITIES: [Abstract]
Accounts payable - trade	17,293		23,210
Deferred revenues	0		0
Accrued liabilities	63,812		73,443
Liabilities of discontinued operations	21,255		21,255
Total current liabilities	102,360		117,908
Long-term debt	2,009,668		2,009,598
Due to affiliates	1,189,031		0
Other liabilities	320,092		323,778
Deferred income taxes - net	121,034		122,814
Shareholders' equity	4,519,312		4,562,016
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	8,261,497		7,136,114
Condensed Consolidating Income Statements [Abstract]
REVENUES	34,359	41,888
COSTS AND EXPENSES: [Abstract]
Direct operating costs (excluding items below)	11,318	6,612
Depreciation and amortization	12,641	12,882
Selling, general and administrative	714	6,029
Loss (gain) on disposals of property and equipment	210	167
Material charges and other operating expenses	0	1,363
Total costs and expenses	24,883	27,053
INCOME (LOSS) FROM OPERATIONS	9,476	14,835
OTHER INCOME (EXPENSE): [Abstract]
Interest expense, net of interest capitalized	(18,581)	(11,053)
Interest income	76	43
Other - net	(2,468)	36
Total other income (expense) - net	(20,973)	(10,974)
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(11,497)	3,861
(Benefit) provision for income taxes	(7,388)	2,128
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	(4,109)	1,733
DISCONTINUED OPERATIONS, NET OF TAX	0	(5,982)
EQUITY IN EARNINGS OF SUBSIDIARIES, NET OF TAX	50,247	50,386
NET INCOME	46,138	46,137
Statement of Comprehensive Income [Abstract]
NET INCOME	46,138	46,137
Pension and other postretirement benefit adjustments, net of income taxes
Amortization of net loss	4,412	4,087
Amortization of transition obligation	0	77
Amortization of prior service credit	(784)	(775)
OTHER COMPREHENSIVE INCOME	3,628	3,389
COMPREHENSIVE INCOME	49,766	49,526
Consolidated Statement of Cash Flows [Abstract]
NET CASH PROVIDED BY OPERATING ACTIVITIES	(12,150)	(16,647)
INVESTING ACTIVITIES [Abstract]
Property, plant and equipment additions	(20,709)	(46,650)
Proceeds from disposals of property, plant and equipment	2,202	0
Investments in consolidated subsidiaries	(86,531)
Increase in restricted cash		(10,038)
Net cash used in investing activities	(105,038)	(56,688)
FINANCING ACTIVITIES [Abstract]
Repayments of borrowings	0	(5,203)
Advances (to) from affiliates	155,193	(56,334)
Contributions from parent	0	0
Proceeds from borrowings	0	0
Debt issue costs	0	0
Dividends paid to affiliates	0	0
Proceeds from exercise of employee share options	0	214
Excess tax benefits from share-based compensation	112	276
Net cash provided by (used in) financing activities	155,305	(61,047)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	38,117	(134,382)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	228,085	184,677
CASH AND CASH EQUIVALENTS, END OF PERIOD	266,202	50,295
Other Non-guarantor Subsidiaries [Member]
CURRENT ASSETS: [Abstract]
Cash and cash equivalents	702,216	271,983
Receivables - trade and other	343,731		328,346
Other current assets	34,567		34,842
Assets of discontinued operations	0		0
Total current assets	1,080,514		1,100,483
Property, plant and equipment - gross	6,428,624		6,349,106
Less accumulated depreciation and amortization	1,152,797		1,102,217
Property, plant and equipment - net	5,275,827		5,246,889
Investments in subsidiaries	0		0
Due from affiliates	774,718		391,008
Other assets	35,081		37,421
TOTAL ASSETS	7,166,140		6,775,801
CURRENT LIABILITIES: [Abstract]
Accounts payable - trade	46,299		58,517
Deferred revenues	50,250		52,340
Accrued liabilities	42,514		64,052
Liabilities of discontinued operations	0		0
Total current liabilities	139,063		174,909
Long-term debt	0		0
Due to affiliates	1,482,868		4,827,445
Other liabilities	64,772		66,421
Deferred income taxes - net	378,798		351,058
Shareholders' equity	5,100,639		1,355,968
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	7,166,140		6,775,801
Condensed Consolidating Income Statements [Abstract]
REVENUES	391,519	326,775
COSTS AND EXPENSES: [Abstract]
Direct operating costs (excluding items below)	229,791	210,713
Depreciation and amortization	51,975	46,084
Selling, general and administrative	19,505	16,386
Loss (gain) on disposals of property and equipment	98	(223)
Material charges and other operating expenses	0	1,533
Total costs and expenses	301,369	274,493
INCOME (LOSS) FROM OPERATIONS	90,150	52,282
OTHER INCOME (EXPENSE): [Abstract]
Interest expense, net of interest capitalized	(38)	(204)
Interest income	279	66
Other - net	(825)	1,301
Total other income (expense) - net	(584)	1,163
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	89,566	53,445
(Benefit) provision for income taxes	10,652	(2,632)
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	78,914	56,077
DISCONTINUED OPERATIONS, NET OF TAX	0	0
EQUITY IN EARNINGS OF SUBSIDIARIES, NET OF TAX	0	0
NET INCOME	78,914	56,077
Statement of Comprehensive Income [Abstract]
NET INCOME	78,914	56,077
Pension and other postretirement benefit adjustments, net of income taxes
Amortization of net loss	0	0
Amortization of transition obligation	0	0
Amortization of prior service credit	0	0
OTHER COMPREHENSIVE INCOME	0	0
COMPREHENSIVE INCOME	78,914	56,077
Consolidated Statement of Cash Flows [Abstract]
NET CASH PROVIDED BY OPERATING ACTIVITIES	120,405	81,694
INVESTING ACTIVITIES [Abstract]
Property, plant and equipment additions	(91,256)	(91,455)
Proceeds from disposals of property, plant and equipment	185	928
Investments in consolidated subsidiaries	0
Increase in restricted cash		(583)
Net cash used in investing activities	(91,071)	(91,110)
FINANCING ACTIVITIES [Abstract]
Repayments of borrowings	0	(7,109)
Advances (to) from affiliates	(150,944)	55,804
Contributions from parent	86,531	0
Proceeds from borrowings	0	0
Debt issue costs	0	0
Dividends paid to affiliates	0	0
Proceeds from exercise of employee share options	0	0
Excess tax benefits from share-based compensation	0	0
Net cash provided by (used in) financing activities	(64,413)	48,695
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(35,079)	39,279
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	737,295	232,704
CASH AND CASH EQUIVALENTS, END OF PERIOD	702,216	271,983
Consolidating Adjustments [Member]
CURRENT ASSETS: [Abstract]
Cash and cash equivalents	0	0
Receivables - trade and other	0		0
Other current assets	0		0
Assets of discontinued operations	0		0
Total current assets	0		0
Property, plant and equipment - gross	0		0
Less accumulated depreciation and amortization	0		0
Property, plant and equipment - net	0		0
Investments in subsidiaries	(9,619,951)		(5,917,984)
Due from affiliates	(2,671,907)		(4,915,488)
Other assets	0		0
TOTAL ASSETS	(12,291,858)		(10,833,472)
CURRENT LIABILITIES: [Abstract]
Accounts payable - trade	0		0
Deferred revenues	0		0
Accrued liabilities	0		0
Liabilities of discontinued operations	0		0
Total current liabilities	0		0
Long-term debt	0		0
Due to affiliates	(2,671,907)		(4,915,488)
Other liabilities	0		0
Deferred income taxes - net	0		0
Shareholders' equity	(9,619,951)		(5,917,984)
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	(12,291,858)		(10,833,472)
Condensed Consolidating Income Statements [Abstract]
REVENUES	(31,640)	(35,186)
COSTS AND EXPENSES: [Abstract]
Direct operating costs (excluding items below)	(31,640)	(35,186)
Depreciation and amortization	0	0
Selling, general and administrative	0	0
Loss (gain) on disposals of property and equipment	0	0
Material charges and other operating expenses	0	0
Total costs and expenses	(31,640)	(35,186)
INCOME (LOSS) FROM OPERATIONS	0	0
OTHER INCOME (EXPENSE): [Abstract]
Interest expense, net of interest capitalized	38	0
Interest income	(38)	0
Other - net	0	0
Total other income (expense) - net	0	0
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	0	0
(Benefit) provision for income taxes	0	0
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	0	0
DISCONTINUED OPERATIONS, NET OF TAX	0	0
EQUITY IN EARNINGS OF SUBSIDIARIES, NET OF TAX	(125,052)	(102,214)
NET INCOME	(125,052)	(102,214)
Statement of Comprehensive Income [Abstract]
NET INCOME	(125,052)	(102,214)
Pension and other postretirement benefit adjustments, net of income taxes
Amortization of net loss	(4,412)	(4,087)
Amortization of transition obligation	0	(77)
Amortization of prior service credit	784	775
OTHER COMPREHENSIVE INCOME	(3,628)	(3,389)
COMPREHENSIVE INCOME	(128,680)	(105,603)
Consolidated Statement of Cash Flows [Abstract]
NET CASH PROVIDED BY OPERATING ACTIVITIES	0	0
INVESTING ACTIVITIES [Abstract]
Property, plant and equipment additions	0	0
Proceeds from disposals of property, plant and equipment	0	0
Investments in consolidated subsidiaries	86,531
Increase in restricted cash		0
Net cash used in investing activities	86,531	0
FINANCING ACTIVITIES [Abstract]
Repayments of borrowings	0	0
Advances (to) from affiliates	0	0
Contributions from parent	(86,531)	0
Proceeds from borrowings	0	0
Debt issue costs	0	0
Dividends paid to affiliates	0	0
Proceeds from exercise of employee share options	0	0
Excess tax benefits from share-based compensation	0	0
Net cash provided by (used in) financing activities	(86,531)	0
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 0	$ 0