COMMITMENTS AND CONTINGENT LIABILITIES (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
COMMITMENTS AND CONTINGENT LIABILITIES [Abstract]
Rental expense attributable to continuing operations	$ 8,000,000	$ 5,600,000	$ 3,700,000
Future minimum payments to be made under noncancelable operating leases [Abstract]
2013	5,120,000
2014	4,778,000
2015	4,243,000
2016	4,250,000
2017	4,080,000
Later years	11,359,000
Total	33,830,000
Status of company's rigs under construction [Abstract]
Total estimated project costs	2,959,000,000
Total costs incurred through December 31, 2012	746,000,000
Projected costs in 2013	751,000,000
Projected costs in 2014	1,014,000,000
Projected costs in 2015	448,000,000
Total future costs	2,213,000,000
Expected capital expenditures in 2013	75,000,000
Outstanding letters of credit	32,900,000
Estimated cost to decommission well	17,000,000
Repair expense on damaged rig	12,000,000
Post-casualty rig valuation	25,000,000
Income tax expense (benefit)	(19,829,000)	(5,659,000)	91,934,000	25,400,000
Number of Asbestos related law suits	18
Rowan Renaissance [Member]
Status of company's rigs under construction [Abstract]
Expected or actual delivery date	Dec-13
Total estimated project costs	730,000,000
Total costs incurred through December 31, 2012	202,000,000
Projected costs in 2013	516,000,000
Projected costs in 2014	12,000,000
Projected costs in 2015	0
Total future costs	528,000,000
Rowan Resolute [Member]
Status of company's rigs under construction [Abstract]
Expected or actual delivery date	Jun-14
Total estimated project costs	738,000,000
Total costs incurred through December 31, 2012	186,000,000
Projected costs in 2013	144,000,000
Projected costs in 2014	408,000,000
Projected costs in 2015	0
Total future costs	552,000,000
Rowan Reliance [Member]
Status of company's rigs under construction [Abstract]
Expected or actual delivery date	Oct-14
Total estimated project costs	731,000,000
Total costs incurred through December 31, 2012	188,000,000
Projected costs in 2013	48,000,000
Projected costs in 2014	491,000,000
Projected costs in 2015	4,000,000
Total future costs	543,000,000
Rowan Relentless [Member]
Status of company's rigs under construction [Abstract]
Expected or actual delivery date	Mar-15
Total estimated project costs	760,000,000
Total costs incurred through December 31, 2012	170,000,000
Projected costs in 2013	43,000,000
Projected costs in 2014	103,000,000
Projected costs in 2015	444,000,000
Total future costs	$ 590,000,000