Marketable Investment Securities (Tables)

9 Months Ended

Mar. 31, 2017

Investments Debt And Equity Securities [Abstract]

Schedule of Fair Value for Available-for-Sale Securities by Major Security Type and Class of Security

The amortized cost, gross unrealized holding gains, gross unrealized holding losses, and fair value for available-for-sale securities by major security type and class of security at March 31, 2017 and June 30, 2016 were as follows:

			Gross		Gross
			unrealized		unrealized
	Amortized		holding		holding			Estimated
	cost		gains		losses			fair value
At March 31, 2017:
Cash and cash equivalents:
Cash	$	106.6	$	—	$	—		$	106.6
Cash equivalents		17.2		—		—		$	17.2
Total cash and cash equivalents		123.8		—		—			123.8
Available-for-sale:
Corporate bonds and notes		41.5		—		(0.1	)		41.4
Municipal bonds		43.5		—		—			43.5
Federal agency issues		11.6		—		—			11.6
US government securities		5.2		—		—			5.2
Total	$	225.6	$	—	$	(0.1	)	$	225.5

			Gross		Gross
			unrealized		unrealized
	Amortized		holding		holding		Estimated
	cost		gains		losses		fair value
At June 30, 2016:
Cash and cash equivalents:
Cash	$	66.1	$	—	$	—	$	66.1
Cash equivalents		2.4		—		—		2.4
Total cash and cash equivalents		68.5		—		—		68.5
Available-for-sale:
Corporate bonds and notes		50.8		0.2		—		51.0
Municipal bonds		85.4		0.2		—		85.6
Federal agency issues		25.5		—		—		25.5
US government securities		8.2		0.1		—		8.3
Total	$	238.4	$	0.5	$	—	$	238.9

Schedule of Maturities of Debt Securities Classified as Cash Equivalents and Available-For-Sale Securities

Cash, cash equivalents, and maturities of debt securities classified as available-for-sale securities are as follows at March 31, 2017:

	Amortized		Estimated
	cost		fair value
Cash	$	106.6	$	106.6
Cash equivalents		17.2		17.2
Available-for-sale:
Due within one year		48.3		48.3
Due after one year through five years		52.0		51.9
Due after five years		1.5		1.5
Total	$	225.6	$	225.5