FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENT (Tables)

12 Months Ended

Sep. 30, 2016

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENT

Summary of available-for-sale securities

	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
	(in thousands)
Equity Securities:
September 30, 2016	$	38,473	$	33,051	$	—	$	71,524
September 30, 2015	$	64,462	$	28,530	$	1,509	$	91,483

Summary of assets measured at fair value on a recurring basis

        The following table summarizes our assets measured at fair value presented in our Consolidated Condensed Balance Sheet as of September 30, 2016:

	Total Measured at Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
Recurring fair value measurements:
Short-term investments:
Certificate of deposit	$	2,000	$	—	$	2,000	$	—
Corporate debt securities		18,591		—		18,591		—
U.S. government and federal agency securities		23,557		18,074		5,483		—
Total short-term investments		44,148		18,074		26,074		—
Cash and cash equivalents		905,561		905,561		—		—
Investments		71,524		71,524		—		—
Other current assets		27,631		27,381		250		—
Other assets		2,000		2,000		—		—
Total assets measured at fair value	$	1,050,864	$	1,024,540	$	26,324	$	—
Nonrecurring fair value measurements:
Assets:
Assets held for sale (1)	$	1,106	$	—	$	—	$	1,106

(1)           Represents the book value as of September 30, 2016 of decommissioned rigs and rig related equipment written down to their estimated recoverable amounts at September 30, 2016. These assets are included in assets held for sale in our Consolidated Balance Sheet at September 30, 2016.

Summary of supplemental fair value information about long-term fixed-rate debt

	September 30,
	2016		2015
	(in millions)
Carrying value of long-term fixed-rate debt	$	491.8	$	531.5
Fair value of long-term fixed-rate debt	$	529.6	$	553.5