Other Financial Statement Disclosures (Details 2) (USD $) Share data in Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended				6 Months Ended						3 Months Ended		6 Months Ended				0 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Jun. 30, 2013 Accumulated Other Comprehensive Income (Loss) [Member]	Jun. 30, 2012 Accumulated Other Comprehensive Income (Loss) [Member]	Jun. 30, 2013 Unsecured debt [Member] Senior Notes due 2017 [Member]	Jun. 30, 2013 Unsecured debt [Member] Senior Notes Due 2019 [Member]	Jun. 30, 2013 Unsecured debt [Member] Senior Notes due 2022 [Member]	Jun. 30, 2013 Unsecured debt [Member] Senior Notes Due 2042 [Member]	Jun. 30, 2013 Rowan Companies, Inc. [Member]	Jun. 30, 2012 Rowan Companies, Inc. [Member]	Jun. 30, 2013 Rowan Companies, Inc. [Member]	Jun. 30, 2012 Rowan Companies, Inc. [Member]	Jun. 30, 2013 Minimum [Member] broker	Jun. 30, 2013 Maximum [Member] broker	Jun. 06, 2013 Rowan Paris [Member]	Jun. 30, 2013 Rowan Paris [Member]
Debt Instrument [Line Items]
Number of brokers who provided fair value of debt securities																			1	2
Stated interest rate (in hundredths)											5.00%	7.875%	4.875%	5.40%
Maturity of debt											Sep. 01, 2017	Aug. 01, 2019	Jun. 01, 2022	Dec. 01, 2042
Shareholders' Equit [Abstract]
Other	$ 1,800,000		$ 1,820,000	$ 0
Number of shares representing the cash received in settlement of bankruptcy court claim				52
Accumulated other comprehensive losses (AOCL)	213,797,000		213,797,000					221,082,000	213,800,000	218,900,000
Amortization of pension and postretirement benefit cost	3,657,000	3,388,000	7,285,000	6,777,000					7,285,000	6,777,000
Supplemental Cash Flow Information [Abstract]
Accrued capital expenditures			36,400,000	39,600,000
Interest capitalized in connection with rig construction projects	11,500,000	7,300,000	22,200,000	14,100,000
Income Taxes [Abstract]
Ownership interest (in hundredths)															100.00%		100.00%
U.S. statutory tax rate (in hundredths)			35.00%
U.K. statutory tax rate (in hundredths)					23.00%	24.00%	26.00%
Gain on Sale of Equipment [Abstract]
Proceeds from sale of rigs																						40,000,000
Gain (loss) on disposals of property and equipment	19,222,000	2,063,000	18,914,000	2,119,000											(19,000)	(1,374,000)	(229,000)	(1,541,000)			19,200,000
Material Charges and Other Operating Expenses [Abstract]
Material charges and other operating expenses	0	8,126,000	0	12,697,000
Redomestication expenses		8,100,000	0	9,800,000
Steel impairment costs			$ 0	$ 2,896,000