Financial Instruments and Fair Value Disclosures (Tables)

12 Months Ended

Dec. 31, 2015

Assets and Liabilities Measured at Fair Value on Recurring and Nonrecurring Basis


	December 31, 2015
	Fair Value Measurements Using						Assets at Fair Value		Total Losses for Year Ended ⁽¹⁾
	Level 1		Level 2		Level 3		Assets at Fair Value		Total Losses for Year Ended ⁽¹⁾
	(In thousands)
Recurring fair value measurements:
Assets:
Short-term investments	$	105,659		—	$	—	$	105,659
Corporate bonds		—		11,438		—		11,438
Mortgage-backed securities		—		80		—		80

Total assets	$	105,659		11,518	$	—	$	117,177

Nonrecurring fair value measurements:
Assets:
Impaired assets ⁽²⁾⁽³⁾	$	—	$	—	$	189,600	$	189,600	$	860,441

⁽¹⁾	Represents the aggregate impairment loss recognized for the year ended December 31, 2015 related to our 2015 Impaired Rigs.

⁽²⁾

Represents the book value of our 2015 Impaired Rigs, which were written down to their estimated recoverable amounts during 2015, of which $14.2 million and $175.4 million were reported as “Assets Held for Sale” and “Drilling and other property and equipment, net of accumulated depreciation,” respectively, in our Consolidated Balance Sheets at December 31, 2015.

⁽³⁾	Excludes five rigs with an aggregate fair value of $2.4 million, which were impaired in 2015, but were subsequently sold for scrap during the year.


	December 31, 2014
	Fair Value Measurements Using							Assets at Fair Value			Total Losses for Year Ended
	Level 1		Level 2			Level 3		Assets at Fair Value			Total Losses for Year Ended
	(In thousands)
Recurring fair value measurements:
Assets:
Short-term investments	$	217,789	$	—		$	—	$	217,789
Corporate bonds		—		15,899			—		15,899
Mortgage-backed securities		—		134			—		134

Total assets	$	217,789	$	16,033		$	—	$	233,822

Liabilities:
FOREX contracts	$	—	$	(5,439	)	$	—	$	(5,439	)
Nonrecurring fair value measurements:
Assets:
Impaired assets ⁽¹⁾	$	—	$	—		$	9,421	$	9,421		$	109,462

⁽¹⁾	Represents the book value as of December 31, 2014 of four of our 2014 Impaired Rigs, which were written down to their estimated recoverable amounts in September 2014 and had not yet been scrapped. All of these rigs were sold during 2015.

Fair Values and Related Carrying Values of Our Debt Instruments


	December 31, 2015				December 31, 2014
	Fair Value		Carrying Value		Fair Value		Carrying Value
	(In millions)
4.875% Senior Notes due 2015	$	—	$	—	$	255.0	$	250.0
5.875% Senior Notes due 2019		506.8		499.7		544.9		499.6
3.45% Senior Notes due 2023		208.0		249.2		232.0		249.1
5.70% Senior Notes due 2039		360.0		497.0		478.5		497.0
4.875% Senior Notes due 2043		455.3		748.9		638.9		748.8