Financial Instruments and Fair Value Measurement (Tables)

3 Months Ended

Dec. 31, 2015

Financial Instruments and Fair Value Measurement

Summary of available-for-sale securities

			Gross		Gross		Estimated
			Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
	(in thousands)
Equity securities December 31, 2015	$	64,462	$	28,895	$	19,829	$	73,528
Equity securities September 30, 2015	$	64,462	$	28,530	$	1,509	$	91,483

Summary of assets measured at fair value on a recurring basis

	Total		Level 1		Level 2		Level 3
	(in thousands)
Short-term investments:
Certificate of deposit	$	2,100	$	—	$	2,100	$	—
Corporate debt securities	25,450		—		25,450		—
U.S. government and federal agency securities	20,158		8,716		11,442		—
Total short-term investments	47,708		8,716		38,992		—
Cash and cash equivalents	848,230		848,230		—
Investments	73,528		73,528		—		—
Other current assets	37,255		37,005		250		—
Other assets	2,000		2,000		—		—
Total assets measured at fair value	$	1,008,721	$	969,479	$	39,242	$	—

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

	December 31,		September 30,
	2015		2015
	(in millions)
Carrying value of long-term fixed-rate debt	$	531.8	$	531.5
Fair value of long-term fixed-rate debt	$	540.4	$	553.5