NATURE OF OPERATIONS AND BASIS OF PRESENTATION (Details)	1 Months Ended	2 Months Ended	3 Months Ended	12 Months Ended
	Jan. 31, 2017 USD ($)	May 22, 2016 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) drilling_unit $ / bbl $ / d	Sep. 15, 2016 USD ($)	May 23, 2016 USD ($)	Dec. 31, 2015 USD ($)
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Number of mobile offshore drilling units | drilling_unit				29
Number of fleet of self-elevating mobile offshore jack-up drilling units | drilling_unit				25
Number of ultra-deepwater drillships | drilling_unit				4
Deferred revenue				$ 114,400,000			$ 50,800,000
Rowan Relentless [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Contingent payments, period of evaluation				12 months
Revenue		$ 30,500,000	$ 173,200,000
Revenue, canceled contract value			130,900,000
Revenue, fair value of derivative associated with early contract termination agreement			6,200,000
Recognition of previously deferred revenue			$ 5,600,000
Outstanding Receivables From Early Contract Termination [Member] | Rowan Relentless [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Outstanding receivables from early termination of contract						$ 215,000,000
Cobalt International Energy [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Exclusive provider contract term (in years)				5 years
Deferred revenue				$ 95,900,000
Cobalt International Energy [Member] | Rowan Reliance [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Outstanding receivables from early termination of contract				$ 19,600,000	$ 95,900,000
Day rate (in USD per day) | $ / d				582,000
Day rate, after March 31, 2017 (in USD per day) | $ / d				262,000
Deferred revenue					$ 95,900,000
Cobalt International Energy [Member] | Outstanding Receivables From Early Contract Termination [Member] | Rowan Reliance [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Outstanding receivables from early termination contract, cash received in period				$ 76,300,000
Deferred Revenue [Domain] | Cobalt International Energy [Member] | Rowan Reliance [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred revenue				86,500,000
Other Liabilities [Member] | Cobalt International Energy [Member] | Rowan Reliance [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred revenue				9,400,000
Contingent Consideration Threshold 1 [Member] | Rowan Relentless [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Additional contingent payments				$ 10,000,000
Contingent payment, threshold price per barrel (in USD per bbl) | $ / bbl				50
Contingent Consideration Threshold 2 [Member] | Rowan Relentless [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Additional contingent payments				$ 20,000,000
Contingent payment, threshold price per barrel (in USD per bbl) | $ / bbl				65
Subsequent Event [Member] | Freeport-McMoRan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Proceeds from contingent payment provision settlement	$ 6,000,000