SHARE-BASED COMPENSATION PLANS (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Compensation cost charged to expense under all share-based incentive awards [Abstract]
Total compensation cost	$ 24,808,000	$ 22,088,000	$ 15,578,000
Less: Discontinued operations	0	(1,003,000)	(1,310,000)
Continuing operations	24,808,000	21,085,000	14,268,000
Stock option activity [Roll forward]
Compensation expense	2,300,000	2,000,000
Rowan Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)	4,500,000
Incentive plan termination date	May 31, 2019
Number of shares available for future grant (in shares)	834,626
Compensation cost charged to expense under all share-based incentive awards [Abstract]
Unrecognized compensation cost related to nonvested share-based compensation arrangements	29,000,000
Compensation expense over a remaining weighted-average period	1.9
Restricted Shares and Restricted Share Units [Member]
Compensation cost charged to expense under all share-based incentive awards [Abstract]
Total compensation cost	18,557,000	15,912,000	13,379,000
Share Appreciation Rights [Member]
Compensation cost charged to expense under all share-based incentive awards [Abstract]
Total compensation cost	5,358,000	5,813,000	2,678,000
Grant vesting term	one-third annual increments
Requisite service period	3 years
Equity instruments other than options [Roll Forward]
Nonvested, Weighted-average grant-date fair value per share, beginning of period (in dollars per share)	$ 15.28	$ 19.76	$ 14.00
Nonvested, Weighted-average grant-date fair value per share, end of period (in dollars per share)	$ 15.28	$ 19.76	$ 14.00
Expiration period	10 years
Weighted-average assumptions used to determine fair values of SARs [Abstract]
Expected life in years	6	5.7	6
Risk-free interest rate (in hundredths)	1.108%	2.269%	2.725%
Expected volatility (in hundredths)	44.30%	49.16%	50.16%
Weighted-average grant-date per-share fair value (in dollars per share)	$ 15.28	$ 19.76	$ 14.00
Stock option activity [Roll forward]
Outstanding, beginning of period (in shares)	1,188,435
Granted (in shares)	260,052
Exercised (in shares)	(26,151)
Forfeited or expired (in shares)	(5,367)
Outstanding, end of period (in shares)	1,416,969	1,188,435
Exercisable, end of period (in shares)	876,442
Outstanding, Weighted-average exercise price, beginning of period (in dollars per share)	$ 27.43
Granted, Weighted average exercise price (in dollars per share)	$ 35.44
Exercised, Weighted-average exercise price (in dollars per share)	$ 20.02
Forfeited or expired, Weighted-average exercise price (in dollars per share)	$ 35.47
Outstanding, Weighted-average exercise price, end of period (in dollars per share)	$ 29.01	$ 27.43
Exercisable, Weighted-average exercise price, end of period (in dollars per share)	$ 24.67
Outstanding, Weighted-average remaining contractual term, end of period (in years)	6.5
Exercisable, Weighted-average remaining contractual term, end of period (in years)	5.8
Outstanding, Aggregate intrinsic value, end of period	7,174,000
Exercisable, Aggregate intrinsic value, end of period	6,933,000
Total intrinsic value of options exercised	400,000	0	0
Share Options [Member]
Compensation cost charged to expense under all share-based incentive awards [Abstract]
Total compensation cost	152,000	239,000	239,000
Grant vesting term	one-third or one-quarter annual increments
Equity instruments other than options [Roll Forward]
Expiration period	10 years
Stock option activity [Roll forward]
Outstanding, beginning of period (in shares)	559,205
Exercised (in shares)	(27,908)
Forfeited or expired (in shares)	(251)
Outstanding, end of period (in shares)	531,046	559,205
Exercisable, end of period (in shares)	531,046
Outstanding, Weighted-average exercise price, beginning of period (in dollars per share)	$ 23.26
Exercised, Weighted-average exercise price (in dollars per share)	$ 21.07
Forfeited or expired, Weighted-average exercise price (in dollars per share)	$ 23.18
Outstanding, Weighted-average exercise price, end of period (in dollars per share)	$ 23.37	$ 23.26
Exercisable, Weighted-average exercise price, end of period (in dollars per share)	$ 23.37
Outstanding, Weighted-average remaining contractual term, end of period (in years)	2.3
Exercisable, Weighted-average remaining contractual term, end of period (in years)	2.3
Outstanding, Aggregate intrinsic value, end of period	4,331,000
Exercisable, Aggregate intrinsic value, end of period	4,331,000
Total intrinsic value of options exercised	300,000	15,900,000	3,600,000
Share Options [Member] | Maximum [Member]
Compensation cost charged to expense under all share-based incentive awards [Abstract]
Requisite service period	4 years
Share Options [Member] | Minimum [Member]
Compensation cost charged to expense under all share-based incentive awards [Abstract]
Requisite service period	3 years
Performance-Based Awards [Member]
Compensation cost charged to expense under all share-based incentive awards [Abstract]
Total compensation cost	741,000	124,000	(718,000)
Equity instruments other than options [Roll Forward]
Granted, Weighted-average grant-date fair value per share (in dollars per share)	$ 100
Fair value of shares vested	0	2,300,000	600,000
Awards vesting period	3 years
Vesting percentage of performance units periodically (in hundredths)	25.00%
Vesting percentage of performance units (in hundredths)	25.00%
Performance-Based Awards [Member] | Maximum [Member]
Equity instruments other than options [Roll Forward]
Expected to vest, weighted average exercise price (in dollars per share)	$ 200
Performance-Based Awards [Member] | Minimum [Member]
Equity instruments other than options [Roll Forward]
Expected to vest, weighted average exercise price (in dollars per share)	$ 0
Restricted Shares [Member]
Compensation cost charged to expense under all share-based incentive awards [Abstract]
Grant vesting term	one-third increments each year over a three-year service period, or in some cases, cliff vest at the end of a three-year service period.
Requisite service period	3 years
Equity instruments other than options [Roll Forward]
Nonvested, beginning of period (in shares)	878,489
Granted (in shares)	678,829
Vested / Settled (in shares)	(503,055)
Forfeited (in shares)	(22,229)
Nonvested, end of period (in shares)	1,032,034	878,489
Nonvested, Weighted-average grant-date fair value per share, beginning of period (in dollars per share)	$ 35.80	$ 31.49
Granted, Weighted-average grant-date fair value per share (in dollars per share)	$ 35.32
Vested / Settled, Weighted-average grant-date fair value per share (in dollars per share)	$ 28.01
Forfeited, Weighted-average grant-date fair value per share (in dollars per share)	$ 27.26
Nonvested, Weighted-average grant-date fair value per share, end of period (in dollars per share)	$ 35.80	$ 31.49
Fair value of shares vested	17,800,000	17,500,000	12,600,000
Weighted-average assumptions used to determine fair values of SARs [Abstract]
Weighted-average grant-date per-share fair value (in dollars per share)	$ 35.80	$ 31.49
Employee Restricted Share Units [Member]
Compensation cost charged to expense under all share-based incentive awards [Abstract]
Grant vesting term	one-third increments
Requisite service period	3 years
Equity instruments other than options [Roll Forward]
Nonvested, beginning of period (in shares)	0
Granted (in shares)	25,236
Vested / Settled (in shares)	(1,092)
Forfeited (in shares)	0
Nonvested, end of period (in shares)	24,144
Nonvested, Weighted-average grant-date fair value per share, beginning of period (in dollars per share)	$ 34.74	$ 0
Granted, Weighted-average grant-date fair value per share (in dollars per share)	$ 34.78
Vested / Settled, Weighted-average grant-date fair value per share (in dollars per share)	$ 35.47
Forfeited, Weighted-average grant-date fair value per share (in dollars per share)	$ 0
Nonvested, Weighted-average grant-date fair value per share, end of period (in dollars per share)	$ 34.74	$ 0
Weighted-average assumptions used to determine fair values of SARs [Abstract]
Weighted-average grant-date per-share fair value (in dollars per share)	$ 34.74	$ 0
Non-employee Director Restricted Share Units [Member]
Equity instruments other than options [Roll Forward]
Outstanding, beginning of period (in units)	207,971
Granted (in shares)	53,217
Vested / Settled (in shares)	(43,072)
Forfeited (in shares)		0	0
Outstanding, end of period (in units)	218,116	207,971
Vested, end of period (in units)	164,899
Outstanding, Weighted-average grant-date fair value per share, beginning of period (in dollars per share)	$ 34.59
Granted, Weighted-average grant-date fair value per share (in dollars per share)	$ 33.82
Vested / Settled, Weighted-average grant-date fair value per share (in dollars per share)	$ 32.36
Outstanding, Weighted-average grant-date fair value per share, end of period (in dollars per share)	$ 32.71	$ 34.59
Vested, Weighted-average grant date fair value per share, end of period (in dollars per share)	$ 32.36
Fair value of shares of common stock issued in connection with settlement of vested RSUs	1,400,000
Performance Units [Member]
Equity instruments other than options [Roll Forward]
Fair value of shares vested	2,300,000
Fair value of long-term liabilities	$ 700,000