Accumulated Other Comprehensive Gain (Loss) - Changes in Accumulated Other Comprehensive Income Loss (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Contract drilling, excluding depreciation	$ 419,488	$ 357,281	$ 1,163,618	$ 1,159,635
Other, net	(326)	168	(746)	767
Income tax expense	36,817	56,661	137,974	168,224
Net of tax	(94,748)	(178,186)	(456,071)	(564,816)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Marketable Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other, net	(15)		(165)
Income tax expense	1		19
Net of tax	(14)		(146)
FOREX contracts [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Cash Flow Hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Contract drilling, excluding depreciation	5,572		2,951
Income tax expense	(1,950)		(1,033)
Net of tax	$ 3,622		$ 1,918